Moderators in game
Since the automated system is so bad it can't even deal with flamers, let alone inters, trolls or afkers (if they move around to cheat the leaver buster), the most respectable members of the community should be appointed by Riot as moderators with the ability to give chat restrictions and bans. Perhaps the chance of running into one in their own game and getting punished right away would discourage people from being toxic at least a little.