User blog comment:Kagimizu/Kha'zix: Adapt and Balance (Kha'zix balance ideas)/@comment-12443575-20140516051859/@comment-1272757-20140516074116

Unfortunately, that's pretty much how it works. If something is SO popular that it's overcrowding the rest of the kit, or if a champion is so popular they're pushing out other champions in the role, then Riot feels the need to nerf that champion to make sure they stand on even ground in terms of viability. I still find Kha'zix fun to use and enjoy playing him (in the jungle; his laning has just been neutered outright), but I feel like the changes they're going with aren't satisfying thematically or gameplay-wise.

I can agree Annie isn't overnerfed. Sona it's more of a thematic issue with the subtlety of her auras and what they do, which Riot is intending to fix in the future.