I've heard good things about MegaKangaskhan. It unfortunately can't learn Zen Headbutt. A good moveset I've seen on it is Fake Out, Power-Up Punch, Earthquake and I think it was Sucker Punch as the last move.
I'm not sure yet how the Megas are affecting the metagame, so I don't know for sure. If we do go for a Mega, which one? The team is pretty good in terms of coverage, but it still can't hit Fire, Poison, or Electric super effectively so maybe MegaGarchomp would be the best fit.
Both Sacred Sword and King's Shield are really good so sure and I'm pretty sure the Ghost (Shadow Sneak)+Fighting combo isn't resisted by any typing except for Normal/Ghost but none exist without using Trick-or-Treat (Happy Hallowe'en, by the way) which I don't think is likely to happen.
I guess you're right about Assault Vest not working well of Aegislash, but oh well it was just an idea. How does Dragon Pulse, Boomburst, Air Slash and Flamethrower sound for Noivern's moveset? Or possibly Dragon Meteor and/or Hurricane, but the drawbacks to the moves aren't desirable. I would include a Steel or Poison move, but it doesn't learn any worth using. Maybe Choice Specs would be better than Assault Vest?
I was thinking Noivern as well since it has the powerful Boomburst to use. For the item, there isn't a whole lot to choose from unfortunately. We might be able to forgo Autotomize and other status moves for Choice Band/Scarf or the Assault Vest. Shell Bell might also prove to be more effective than Leftovers if Aegislash can deal out lots of damage/turn, but the HP-restoring property is in the same vein as Leftovers.
Aegislash would definitely bring some offensive/defensive (depending on form) power to the team. I haven't trained an Aegislash myself, so I don't know all that much about it, but maybe replacing Iron Defense with Autotomize would be beneficial since, if max Speed, it can use Autotomize at the beginning while still in Shield Form to raise its Speed to a quite respectable 480 and then switch to Blade Form and start attacking. I don't know...
Although if we do go for two Steel types, we'll definitely need something to take Fire and Ground attacks for them. Dragon/Flying or a Water and something else might be our best bets.
It seems we have. (Do you wish to continue?) Both Focus Sash and Volt Switch would work well, like you said. And, I agree with the last line; part of the reason I play competitive battles on and off is that the metagame gets stale with having the same Pokemon with the same sets show up battle after battle meaning that a certain move or Pokemon needs to be used to counter it.
Possibly a Magnezone (or Magneton with Eviolite) with Thunderbolt since Magnezone resists Flying and can hit Skarmory for SE with it and, if need be, it can run HP Fire. Magnet Pull also makes Skarmory unable to escape.
So, it has max Speed, and an EV split between Sp Att and Att. It's moveset consists of U-Turn, Hi-Jump Kick, Aura Sphere and Hidden Power Ghost. U-turn allows it make good use of Renerator, Aura Sphere lets it use a strong STAB move without having to run the risk of missing and getting bad recoil, and Hidden Power for hitting Ghosts/Psychics on the switch. I've yet to test it, though.
Partly just curiosity and partly because I've thought up a set for a potential mixed-attacker Mienshao (all the ones I've seen are physical attackers), but I know you're aiming more for defensive/tankish Pokemon. If you want, I can tell you my idea for it.
I've done a few without tails before, like Froakie and Surskit. But I dealt with those by giving the former a 'bubble tail' and the latter I used it's back legs.
Klink would probably be a bit harder than those, but with enough creativity, I probably would have been able to have made something work.
Hoo boy, I gotta admit, this one turned out great-
Top - http://i43.*******.com/2zhe2x5.png
I hope you don't mind, but it looked better having the tails intertwine halfway instead of staying permanently wrapped around each other. And it was much more fun to animate. Though, tell me if you'd rather I change it, because I can most certainly do so~