funny thing is i was testing out custom games and found you can create very decent control games with the ai. you just need to pick the right heros on hard setting and adjust the speed and damage and you get yourself quite a balanced quickplay style game.
the benefit is also ai will group up. will combo and counter ult, will use peel abilities and they can aim.
they really should work on their ai and improve it and i bet you could get close enough to real style games.