None of which apply specifically to league only, and you don't see a core game ending 6v1 9/10, sorry!
Thats because core games get new players if someone leaves the game. That doesn't happen in league. That is why it is so noticable.
If a player leave the game I think they should use bot replace the player that leave the game. Then its always be 2v2 or 6v6 players on each side.
If Treyarch keep banning people the way they are hopefully people will eventually cotton on and reign it in!