While this hype for the three highlight abilities, Stakeout, Dazzling, and Corrosion, are VERY HIGH right now in casual competitive Smgon battles, online rankings, and VGC, just think of the scary implementations of those three in Smogon's Monotype Format, Hackmons, and their own made Almost Any Ability Mode. Gosh, let the anti-buffing begin.
All of these three abilities are like designed to debuff switching and Volt-Turn tactics, all forms of priority attacks andor abilities that gives certain types priority (Prankster and Gale Wings), and destroy Stall team builds so hard.
AAA: Return of the CurseBreon. Now with Corrosion.
But these are just still three pokémon with these abilities.. Outside of Dazzling, Bruxish doesn't look impressive. Yungoos probably has a stat-total similar to a Patrat, so we shouldn't expect much from Oldgoose, since it won't have Huge Power like Diggersby. I honestly doubt that it will force switches that often to get enough boosts to actually turn into something threatening. Everything should have at least something to deal with a Normal-type, unless you're running Mono-Ghost moves, you should just stay in and run your standard strategy and it won't get any buffs. Just a simple Toxic and stall, WoW and stall, or KO it with Fighting-type moves and whoops, no boosts. This isn't designed to debuff Volt-Turn, but if it is, it's just a gimmicky attempt at trying.
Salandit looks great. Hooray! It can poison Poison-types! Hooray! It can poison Steel-types! But why would a Fire-type want to Poison a Steel-type if it can just roast it alive? The only two critters where Corrosion comes into play would be Mega Venusaur (Thick Fat).. all other Poison-types in OU are weak to Fire.. Except Gengar, which should fall to a Fire Blast though..
And for most of the Steel-types, being badly poisoned doesn't do much aside from setting a timer. Salandit would be better off burning more of them, if not with a Fire Blast, then with a Will-o-Wisp. The only ones I can see being handy to Toxic would be Jirachi (before it goes into Flinch-spam) and Heatran. In fact, lets do a breakdown:
Corrosion, for what it's worth as opposed to outright Fire Blasting or Will-o-Wisping:
- Bisharp: Burn or KO with Fire Blast
- Excadrill: Burn or KO with Fire Blast
- Ferrothorn: 1HKO with Fire Blast
- Gengar: 1HKO with Fire Blast
- Heatran: Toxic with Corrosion
- Jirachi: Toxic with Corrosion. Most run the Iron Head-flinch, so rack up damage during the turns you're flinched. Other sets run Wish/Protect, so Toxic works better then a burn or outright attacking.
- Klefki: KO it with Fire Blast, should be doable.
- Magnezone: KO it with Fire Blast
- Mega Metagross: Burn it. I'm assuming that Salandit will just be able to outspeed it, but not outright 1HKO it.
- Scizor: 1HKO it with Fire Blast
- Skarmory: Gets it down to Sturdy with a Fire Blast, will probably get Whirlwinded out.. but if you have SR up, it's a 1HKO probably.
- Mega Venusaur: Toxic it with Corrosion.
So out of the 13 Pokémon in OU that this ability has an effect on, it appears that it is only worthwhile on three. And then you have to wonder how long you're going to outlast them, or if you're running Salandit purely to Toxic those threats (with standard Fire-offensive pressure for the rest). I could see a good set being Toxic, WoW, Fire Blast and something that might pop up in its learnset like Knock Off..