Fix The System (AFKs, Feeders, etc.)
One major flaw in this game is the fact that AFKs and Feeders just simply don't get punished enough. The sole fact that intentionally walking down to the enemy's nexus for the whole game and feeding gets you a low queue timer whilst a person who starts to get annoyed and rages at them gets a 2 week ban is irrefutable.
Being toxic usually stems from these types of players, and its not fair at all. Breaking rules in the actual game don't get you banned, yet being "toxic" does? (it should but I hope you guys get the point)