Faction Battles

I know you can create Custom games to allow players to fight in factions, but has Riot ever tried to create a fun game mode that simply restricts your champion pools to specific factions (i.e. Demacia, Piltover, Shurima, etc.)? Each match the two teams would be assigned a random faction from Runeterra and the 5 players would have to choose champions from that faction. It doesn't necessarily have to do with the actual lore. It would just be a cool twist on champion select. IT would also be cool for the aesthetics of your team to match during the game.

What do you guys think? What faction would you want to represent? What faction would you want to fight?