Lore/Gameplay Idea: Faction Allegiance

I was thinking it might be cool to implement an out of game system where you as a summoner pledge allegiance to one of the factions. This could be pretty cool because people are already a bit crazy about the factions, but also because it could also be used to earn in profile icons or customizations. Also it could give you skin wards or particular champion skins.

Maybe even link it into leveling up so many champion masteries to max of that faction. (like 5) But it could be a cool way to expand some of the lore with players in small visual ways and also result in understanding what factions the player base finds the most interesting.