AR Urf

Quick question. Why does it only select champions we own? If the whole point is to be random, to negate what particular players were doing to abuse normal urf, why does it only select from the champions they own? That doesn't fix the problem, that just makes it worse. If they were to make it so it selects from any given champion in the game, then wouldn't that, at the very least, even the playing field a bit more? I've never seen a non-one sided urf match before. It's obvious that despite how good of an idea AR is, it's an incomplete idea. It's not doing what it is designed to do.