New Game Mode Idea

So I'm a relatively new player (only playing since January) but I really love the ideas of the rotating game mode que. So before I starting playing everyday I went through every champion on the list and read the back stories and stuff. One thing I notified is that there are specific areas where the majority of champions are from. One thing that has always interested me in any game or lore is faction wars. So I came up with the idea that if Riot made a map where it was actually a battle royal of 4 different factions. Basically there would be four teams of five and each team could only pick champions from a certain faction. Yes I'm aware certain champions like A-Sol couldn't be a part as he is the only champion from wherever he is 0-0. But I was thinking the four main regions, The lonely Isles, Demacia, Piltover (with the yordles), Ionia, and Noxus, The map could be a circle and have a team on each side. I'm not too sure how the winner would be decided as I don't know how the easiest way for them to do it is. I would imagine it could basically just be a giant team deathmatch basically with the winning team getting to a certain number of kills first. I'm aware this may not be a great idea but I have always wanted somethin like this so if you guys have any input on this about how it could be refined or just ideas on how to make it better please let me know!!! Thanks!! The Wolf of Nigh