Yes, but League was designed as a 5v5 PvP game on Summoner's Rift, and porting the champions over to a Co-op vs. minions game would lead to massive differences in power level of those champions. That's the imbalance he's talking about.
That issue is present in every other map that isn't Summoner's Rift, but it would become more apparent if you warp the game even more.