Aegislash: The End of an Era
After a lot of suspect testing, intense discussions, and a very close vote, Aegislash has finally been banned from Smogon OU. As with all Pokemon that are banned from a tier, Aegislash's departure has caused a lot of changes in the metagame. However, Aegislash's ban in particular has had a much more drastic effect on the metagame than the ban of many other Pokemon in that past. Back when it was OU, Aegislash's enormous popularity among OU players and effectiveness in battle made it the kind of Pokemon that you had to have an answer to or you were going to face the consequences. Not only that, but nearly every offensive Pokemon had to make sure that they had some way to hit Aegislash due to its dominance in the tier. Thanks to Aegislash's unique typing and great bulk in Shield Form, this required many Pokemon to run coverage moves that they might otherwise have no use for just to hit the undisputed king of OU. Likewise, many Pokemon received boosts to their viability simply for the fact that Aegislash existed. With such a dominating Pokemon pulled out of the metagame that it once ruled, many Pokemon have been impacted significantly – for better or for worse.
Pokemon that Benefitted from Aegislash's Ban
Obviously, there are tons of Pokemon that benefitted from Aegislash's ban. Aegislash checked and pressured so many Pokemon that every single one of them technically got a little better simply due to the fact that one of their checks is now gone. However, there are a handful whose increased viability can be felt more intensely than others, many Pokemon who were powerhouses just waiting for Aegislash to stop holding them back. I'll try to address as many examples as possible, but it might be impossible to cover everything due to the raw number of Pokemon that were pressured by Aegislash.
Mega Medicham
If there's one thing you know about Mega Medicham, it's that it has raw power, and a lot of it. With an effective base 249 Attack stat and a 130 base power STAB move, Mega Medicham boasts some of the highest raw power output in the entire game. Its main problem? Aegislash. It just so happened that the most common and influential Pokemon in the metagame walled its STAB moves and just about every coverage move it ran as well. Mega Medicham's only real way of getting around Aegislash was Fire Punch, but even then, Aegislash could mess that up with King's Shield. If you couldn't catch the Royal Sword Pokemon on the switch with the move, Mega Medicham was forced to switch out. Now that its biggest adversary is gone, Mega Medicham is much freer to run around and spam its super power STAB moves everywhere. It also no longer has to run Fire Punch for Aegislash, which opens it up to other options such as Ice Punch for Landorus-T and Gliscor, one or both of Fake Out and Bullet Punch for handy priority, or even Substitute to scout switches and put enormous pressure on opposing offense. Mega Medicham has quickly become a much more powerful Mega Pokemon, striking fear into the hearts of defensive and offensive teams alike with its insane power.
Mega Heracross
Mega Medicham has a lot of power, but Mega Heracross isn't too far behind. With the exclusion of Mega Mewtwo X, Mega Heracross has the most physical power in the game in terms of raw base stats. While some other Pokemon such as Mega Mawile and Mega Medicham might have certain abilities that boost their power to obscene levels, Mega Heracross has a special ability of its own to make it even more dangerous: Skill Link. Thanks to this ability and the new multi-hit moves that Heracross received in XY, Mega Heracross has become a phenomenal wallbreaker capable of blowing teams wide open with its 120-125 base power STAB and coverage moves. The only real problem it had before was Aegislash. Mega Heracross was forced to run Earthquake in order to reliably beat Aegislash, which hurt its ability to run other coverage or utility moves alongside the otherwise great coverage between Pin Missile, Close Combat, and Rock Blast. Thanks to Aegislash's ban, it can now run moves like Bullet Seed to better hit bulkier Pokemon such as Hippowdon and Suicune, Swords Dance to plow through slower teams after a boost, and Substitute to protect itself from status and switch-ins and put enormous pressure on opposing offense. A super powered bug that was forced into a rut before has now gained a significant amount of freedom thanks to Aegislash's departure.
Mega Gardevoir
Mega Gardevoir is well known for spamming its Pixilate-boosted Hyper Voices everywhere. While it's not quite on the level of Mega Medicham's High Jump Kick, Mega Gardevoir's Hyper Voice has the advantage of having no immunities, being perfectly accurate, and not wiping out half of Mega Gardevoir's health if it messes up. Oh, and it bypasses Substitutes, too! The big problem with Aegislash was not just that it resisted Hyper Voice; it also heavily resisted Mega Gardevoir's main secondary moves, Focus Blast and Psyshock. Without Shadow Ball, Mega Gardevoir struggled to break past Aegislash at all. Of course, that's no longer a problem, leaving Mega Gardevoir with a free moveslot for one of many other utility moves. It can use Will-O-Wisp to cripple physically based checks such as Scizor, it can use Taunt to put a stop to opposing status moves and put huge pressure on defensive teams, and it can even use Calm Mind to boost its power to insane levels and even increase its already solid special bulk. Mega Gardevoir's combination of power and reliability has made it one of the more solid Mega Pokemon in today's metagame, especially with Aegislash done away with.
Terrakion
Terrakion has been a solid contender in OU ever since BW. In fact, it was one of the big faces of BW OU offense, and most of its old roles have carried over in the generation shift. Its biggest problem was – you guessed it – Aegislash. Terrakion is infamous for its nearly unresisted coverage between its Rock and Fighting STAB moves alone. Only a handful of Pokemon resist that coverage, and the biggest one just happened to be Aegislash. Unless you absolutely need those two extra moveslots (i.e. in the case of Stealth Rock + Taunt sets), Earthquake was practically mandatory on Terrakion just for hitting Aegislash really hard. Post-ban Terrakion has much more freedom. Stealth Rock lead sets have become much better since Aegislash is no longer around to wall the Rock + Fighting combination. SubSD + Salac Berry, an old relic from BW OU, has returned to wreak havoc on defensive and offensive teams alike. In fact, Life Orb sets in general have become complete wildcards since all you can really be sure of is that Terrakion has Close Combat and Stone Edge. Does it have HP Ice for Landorus-T and Gliscor? Does it have Substitute to block status and scout switches? Does it have Swords Dance to pulverize slower teams or Rock Polish for faster ones? There are tons of possibilities now that Terrakion can slam most of the metagame with its STABs alone and has half its moveset open for case-by-case utilities.
Mega Pinsir
Mega Pinsir hasn't changed all that much since Aegislash was banned, but it has still gained a little more freedom like many others. Back in the Aegislash metagame, Mega Pinsir really needed to run Earthquake as its coverage move of choice alongside its Flying STAB lest it be walled by Aegislash. That is no longer the case, enabling it to run Close Combat. If there's anything we've learned from Pokemon like Staraptor and Hawlucha (and Tomohawk, for you CAP players), it's that Flying + Fighting has really solid coverage overall. Aegislash, unfortunately, just happened to be one of only a couple of Pokemon to resist that combination. Now that it's out of the way, Mega Pinsir is much more free to run Close Combat as its coverage move of choice. That isn't to say that Earthquake is useless, but overall, Close Combat offers most of the same neutral coverage with more power in general. It also helps Mega Pinsir to get past Rotom-W and Skarmory since it hits both about 21% harder than Return, requiring much less wearing down before they can be defeated.
Starmie
It would be silly to pretend that Starmie's only problem this generation has been Aegislash. You also have to take into account competition as a fast offensive Water-type from Greninja, new checks and counters, etc. However, one of Starmie's biggest niches is Rapid Spin, and Aegislash certainly put a hamper on that. Not only could it switch in and block Starmie's Rapid Spin, but it can also hit it hard back with Shadow Ball or even Pursuit trap it and prevent it from ever spinning. With that one obstacle out of the way, Starmie has started to ascend once again as a popular Rapid Spinner. Offensive sets are still pretty powerful thanks to Starmie's high speed, decent power, and ability to slam switch-ins with Analytic-boosted attacks. Bulky spinning sets are far more viable with Aegislash gone. They are great additions to hazard heavy defensive teams that don't want to remove their own hazards with Defog, and Reflect Type variants are particularly good for spinning in the face of potential checks such as Ferrothorn and Choice Tyranitar.
Latios / Latias
The Lati twins have both definitely improved with the removal of Aegislash, and it isn't hard to see why. Not only was Aegislash capable of switching into their STAB moves and most coverage moves with ease before slamming back with Shadow Ball, but it could also Pursuit trap either of them and remove them from the game entirely. It was easy to just slap Aegislash onto your team in order to pulverize either of the Lati twins, which was great if you had heavy hazard support and didn't want to worry about Defog later on down the road. Now it's a different story. Latios and Latias both are much more free to support their team with Defog, pivot in and out of Pokemon such as Charizard Y and Keldeo, and throw off powerful attacks of their own without worrying about such a potent Pursuit trapper putting them in a checkmate position. That isn't to say that they don't have Pursuit problems at all anymore (Hi, Tyranitar!), but Aegislash was easily one of the biggest ones, and it's no longer a problem.
Breloom
Joining the club of "Pokemon whose STABs were walled by Aegislash," it's obvious that Breloom breathed a sigh of relief when Aegislash was banned. Unlike many of the other Pokemon on this list, Breloom generally didn't run a coverage move for Aegislash; it just didn't have the room. While Bulldoze was an option, Rock Tomb was too important due to the fact that it kept Breloom from being shut down by many common Flying-types such as Charizard Y, Talonflame, and Zapdos. Nowadays, Breloom doesn’t have that problem. It can much more freely run sets focused around its STAB moves with Rock Tomb here and there for additional coverage, and it doesn't have to worry about being so easily shut down. While it may not reach the same level of effectiveness that it enjoyed in BW OU, it definitely has improved.
Azumarill
Azumarill is one of many Pokemon that relies heavily on contact moves to do damage, and as such, it was checked quite well by Aegislash thanks to King's Shield. The thing that sets Azumarill apart is that it was already such a powerful Pokemon even when Aegislash was around due to its high effective base Attack stat, great typing, solid bulk, and ability to run several viable sets. Aegislash was often offense's best answer to Azumarill (and offensive Fairies in general), and with it gone, offense has lost a great check to such a dangerous Pokemon. Now Azumarill no longer has to worry about Aegislash dropping its Belly Drum-boosted Attack to far less impressive levels and doing solid damage of its own before going down, nor does it have to worry about its Choice Band and Assault Vest sets getting curb stomped at -2 Attack. The way Azumarill plays hasn't changed much (you might feel more free to run Superpower > Knock Off now for Ferrothorn, but even then, Knock Off is a great move in general), but it certainly has lost an important check and has quickly become one of the most solid Pokemon out there.
The Birds
I'm sure anyone who has spent a lot of time in the competitive community has heard the term "Bird Spam" thrown around before. It should be no surprise that with one of the best Flying resists in the tier gone, Bird Spam in general has gotten significantly better. Staraptor can more freely spam its ridiculously powerful Reckless and STAB-boosted Brave Birds and Double Edges, hitting most of the Pokemon that resist them hard with Close Combat. Hawlucha has great neutral coverage between its STABs alone, and like Terrakion, it strongly benefits from the tier's premier Ghost / Steel Pokemon being gone. Now it has become a much more solid threat thanks to the ability to boost its speed and power to great levels with Unburden and Swords Dance, respectively, while hitting just about everything hard with High Jump Kick and Acrobatics. Talonflame may not seem like a Pokemon who greatly benefitted from Aegislash's ban thanks to its Fire typing, but Aegislash was actually able to beat Talonflame 1-on-1 if it could catch the Scorching Pokemon with King's Shield as it used Flare Blitz. One more obstacle out of the way, one more point for Bird Spam.
Steel / Psychic Pokemon
Bronzong and Jirachi had two big problems while Aegislash was around. First of all, Aegislash was obviously a solid and common answer to both. It could switch into their attacks pretty well overall and destroy either of them with a STAB Shadow Ball, possibly even Pursuit trap them if it was running the move. Not only that, but it gave both enormous competition as a bulky Steel-type thanks to its better secondary typing, greater offensive pressure, etc. Aegislash's ban hasn't exactly turned either into top tier choices, but both are a lot better off now. Bronzong has risen as both a Stealth Rock support and a check to Sand-based teams that often rely on Excadrill for a sweep, which Bronzong just happens to check handily. Jirachi has gone back to doing much of what it was doing last generation. As a bulky Steel-type with Fighting neutrality, Jirachi is a pretty nice answer to key offensive Pokemon such as Mega Gardevoir, non-Dark Pulse Greninja, and the Lati twins for defensive and balanced teams. It may not be the incredible Pokemon it was back in BW OU, but it's significantly better than it was back in the Aegislash metagame.
Other Fairy- and Psychic-types
It would take forever to go through the many Fairy- and Psychic-type Pokemon that improved as a result of Aegislash's ban. Many of them generally faced problems from Aegislash due to its resistance to their STAB moves and ability to not only hit them hard with its own STAB moves, but also to Pursuit trap them in the case of the Psychic-types. Some of them might have been able to hopefully keep Aegislash at bay with certain coverage or status moves, but there was always the threat of that dreaded Steel / Ghost thing waiting around every corner. The removal of such a popular and dominant check has definitely eased the lives of each of these Pokemon, allowing players to more comfortably put them on many teams. It's a good thing, too, because the viability increase in many of the aforementioned offensive Pokemon thanks to Aegislash's ban has caused a need for many of these Pokemon on some teams. For instance, bulky Psychic-types like Mew and Slowbro make great counters to Mega Medicham, and Unaware Clefable can check Swords Dance Mega Heracross decently enough. Mega Alakazam can even check Sand Rush Excadrill thanks to Trace, which has become more popular as time goes on.
Pokemon that Suffered from Aegislash's Ban
While there were a lot of Pokemon that benefited from Aegislash's ban, there are also a few that suffered from it as well. Believe it or not, Aegislash's very existence in the metagame actually caused a couple of Pokemon to become better simply because they were some of the few good answers to Aegislash out there. Here are some of the main ones.
Mandibuzz
Mandibuzz got a lot of buffs in the transition to XY. Defog became a much sought after utility, the Dark buff made Foul Play more spammable, Overcoat was buffed to absorb any powder-based moves (notably Spore and Sleep Powder), and Knock Off…well, 'nuff said. Another cool thing about Mandibuzz was that it could generally handle Aegislash really well. Outside of SubToxic and the rare Head Smash (as well as possibly Flash Cannon, depending on Aegislash and Mandibuzz's sets), Mandibuzz could switch easily into Aegislash and threaten it with a super effective Foul Play, which ignored the Attack drop of King's Shield. So where is Mandibuzz now? Well, it's still a solid Pokemon even with Aegislash gone. It still checks several key Pokemon such as Gengar and Landorus really well, and it's still a reliable Defogger with its excellent bulk and decent typing. Still, it really stinks for Mandibuzz that one of the biggest threats it could check is now gone.
Chesnaught
Chesnaught is another Pokemon who got a lot of attention early on simply for the fact that it could handle the most common Aegislash sets thanks to its Hidden Ability: Bulletproof. Like Mandibuzz, Chesnaught hated to have to take on the SubToxic sets and those with Flash Cannon, but otherwise, it was fair game. Chesnaught's immunity to Shadow Ball and great physical bulk let it tank most of Aegislash's attacks with ease and either wear it down with Leech Seed and Spikey Shield or even outright KO with Earthquake. Aegislash's ban definitely has taken its toll on XY's residential Grass-type starter as such. It still has its uses, however. Sand offense featuring Excadrill has become more and more popular as of late, and Chesnaught just happens to be able to counter Excadrill and any form of Tyranitar not carrying Fire Blast (or Ice Beam with significant Special Attack investment). It also counters or checks other powerful sweepers such as Mega Gyarados and Terrakion, which is helpful, not to mention that it shuts down any Gengar relying on coverage between Shadow Ball / Focus Blast / Sludge Bomb. It's far from a useless Pokemon in the Aegislash-less metagame, it just lost a big niche as an Aegislash check.
Bisharp
Bisharp has taken quite a hit due to the last two bans. DeoSharp was a household name across the competitive community due to how effective the Deoxys-D + Bisharp combination was. Deoxys-D set the hazards and Bisharp dissuaded Defog to better protect them. Even after the Deoxys forms were banned, Bisharp still had a solid niche as the best Aegislash trapper since, unlike most other Pursuit trappers, it didn't care about the King's Shield Attack drops thanks to Defiant. Now, sadly, that niche is gone as well. That said, it would be foolish to dismiss Bisharp as a non-issue just because Aegislash has been banned. It's still one of the best deterrents to Defog in the entire metagame, and it still has that dangerous STAB Knock Off to toss around. Any offensive team that wants to protect its hazards from Defog will certainly appreciate having Bisharp around. The only difference is that it's not as unique as a Pursuit trapper as it once was.
The Answer to Everyone's Problems…Doublade?
So as you probably noticed, some of the first Pokemon mentioned as beneficiaries of the Aegislash ban are powerful wallbreakers. It was predicted before the Aegislash test was completed that a ban would result in an increase in these powerful wallbreakers and as such would put even more pressure on defensive teambuilding. Unsurprisingly (and to the dismay of many a stall player), the predictions have come true, and many of these offensive Pokemon have become more common and more dangerous due to their increased freedom. It wasn't long before a spark of creativity inspired a new solution for defensive team styles: Doublade. With so many of these wallbreakers dropping their old Aegislash coverage for more generally useful moves, Doublade is able to swoop in and wall their main sets. All it needs is a specially defensive spread to be able to escape 3HKOs from any Mega Gardevoir, Mega Heracross, Mega Medicham, Terrakion, Mega Pinsir, etc. that aren't running super effective coverage moves (and many of them no longer do). Even outside of those key offensive threats, it's also a solid check to other offensive Pokemon such as the Lati twins and Breloom. So is Doublade just a passing fad, or is it the next big thing for stall? Will these wallbreakers start running their old coverage moves again just for Doublade, or will it ever be common enough for them to have to worry about? Only time will tell, but for now, Doublade is a unique answer to a unique problem, and it does its job pretty well.
Conclusion
It's obvious that when you ban a powerful and influential Pokemon from a metagame, it's going to have a major impact on the resulting metagame. As far as Aegislash goes, few Pokemon have singlehandedly impacted the metagame to the extent that Aegislash has. Many Pokemon have grown better as a result of this simple ban, and a few others have gotten a little worse. Just like removing the wrong piece in a game of Jenga, removing Aegislash has caused a cascade of effects that will continue to work themselves out as the metagame develops. Who knows what direction it'll take next?