Personally I love the idea of a league of legends MMO, being a Noxian or a demacian or any of the factions citizens or races would be awesome. Exploring the world fighting for good or even your faction would be awesome. I know it would be difficult to get on its feet, and would be hard to do anything different but I think it would be a success. Riot seems very keen on world building and they're doing a pretty awesome job of it, they've been innovative with creatures and environments for the world. It would be interesting since Riot hasn't made a real second game, I know the mini games on sights and apps or the board game. But those don't really count in my opinion, I know this would be difficult to pull off and Riot tends not to listen to their player base except for extreme circumstances but if enough people asked for this it could gain some footing. Just a thought and hope it sparked some interest.