Did you know that Chandelure’s Hidden Ability has been changed from Shadow Tag to Infiltrator? This opens up the possibility of other Pokémon to have one (or more) of their Abilities to be changed (at least, it sets a precedent)! Any specific Pokémon in mind whose Ability/(ies) you’d like to be changed?
Well, it’s worth pointing out that there has never been a Chandelure with Shadow Tag – Dream World Litwick were never released in generation V, and to my knowledge no AI opponent ever used one either, not even Ingo and Emmet, so they’re changing something that only ever existed in unused coding and our own fevered power fantasies anyway. I doubt this is an indication that they’re willing to start mucking around with existing abilities that are actually used in practice, and I wouldn’t call it a precedent for that. (EDIT: However, the fact that Scolipede’s was changed from Quick Feet to Speed Boost absolutely is. Derp. Doesn’t really change the rest of this answer anyway, though.) For the most part, abilities I’d want to see changed are the ones that are just insultingly bad, like Run Away, Keen Eye and Illuminate, and personally I would fix those by improving the ability itself (see e.g. Lightningrod and Storm Drain), not by changing which Pokémon received it. I can’t think of any off the top of my head that I would actually want to redistribute, though there are probably at least a couple out there.