20 player game mode?

What if there was a game mode on Summoner's Rift where there's 20 players?

5 of your team's players would start on the map and another 5 on a different "dimension" of the same game that looks exactly like Summoner's Rift (except maybe with a different color scheme or with a crumbling world's look, but same layout). You can travel between the two dimensions if you walk into the Nexus. Your mini map would only show the champions in your dimension at any given time.

So while the game starts as 5 v 5 in 1 dimension and 5 v 5 in another dimension, as the game progresses its really a 10 v 10 with people moving tactically between the two dimensions to try and control the game. The game only ends when BOTH Nexus are destroyed.

To deal with potentially increased game length, champions can level up to a higher number (I don't know, maybe 25 or 36) so that games can be closed out once one team gains a significant level advantage.

It would open all sorts of possibilities or do you think this just makes things too messy?

I would imagine the meta would start with 2 mids, 2 tops, 4 bots, 2 JGs but it could evolve in any number of directions once you consider resource/gold/exp management across 2 dimensions and the dynamics of a potentially 20 player brawl in one dimension.