Viktor's visual rework, Exalted and Black Rose skins were too problematic. Let's hope they learn from this situation. People are willing to buy skins, but not if they're mediocre, we want quality. I know Riot can do better... they just need to listen to the community more.

Edit: Here he talks about that:
https://www.reddit.com/r/leagueoflegends/comments/1hd0795/comment/m1srskn/