Riot keeps creating systems to punish those who AFK or leave a game
Why don't they go to the source of the problem. Instead of retroactive punishment, why don't they create a system that PREVENTS toxic games?
Create a queue that allows people to join games in progress with leavers/afk'ers. Lessen the punishment for leaving a game. You'll have less angry people that leave(feeling like they're wasting time in a lost cause) and less people angry AT those leavers(they get a replacement who's likely both positive and better skilled).
Allow those that leave to join other games, while at the same time costing them a penalty in IP/LP(like dodging queues). Then provide people who join games in progress an incentive(the leavers IP/LP + Whatever they would have earned themselves)