Custom Skins
I know custom skins already exist but it would help i summoners could create there own in game it would add so much more to league of legends, because when you get into a game you will see these new custom skins that anyone could make. To be able to make a custom skin you would have to buy the parts (with ip) such as armor, shields, abilities and even the backing effect. Then make it out of game like runes make your custom skin then it would be able to be selected like a normal skin would.
I know this would take a pretty long time for Riot to add this new feature but it would make any game more entertaining seeing everyones custom skins. Once (or if) you make this u could add parts which would be a lot easier then adding a new skin.
Some of the parts could be multi-compatible with different champions. For example a tornado part which Yasuo and Janna could both use.