(UI Concept)

With everything else in this game having different skins and models, what is the feasibility of having User Interface (UI) skins? Many users might enjoy different sound effects and visual themes based on seasons, holidays, or even a single champion or a group of them.

I guess the closest equivalent I can think of is how consoles OS's have different thematic skins available beyond the base.

Could be another market for your users Riot! :D