Soraka is a good example of what Riot can do to niche picks
In retrospect, I find it funny how in S5 Soraka was considered a trash pick, one of the worst champions in the game. I was Silver then and didn't know much about the game. But she got me my first Diamond and it feels good reflecting on that. This was when Soraka had no CC at all, her Q being an AP scaling self-heal based on how many people were hit by it. Literally, a niche pick no one thought much about.
Since S6, Riot had decided to give her much attention and jerked her around with constant meta defining changes and it resulted in the dirty pick it has been since and no one remembers it for what it was like before.
It's a pretty good example of how badly Riot will ruin a niche champion pick if they get their filthy hands on it too much without considering that in mind. It's pretty sad Soraka suffered this fate but I still have Singed and a few other pocket picks in training like Karthus to look forward to.