AFKers and the leaver Buster system
I think anyone who goes afk in ANY ranked match, weather intentional or unintentional should take the loss for their teammates, and if the 4 man team wins that leaver STILL gets 5 total losses to their match history and losing LP 5 times, one for them, and 1 for each of their team mates, also in turn putting them in LPQ, also matching them with other "leavers" to make them feel the same pain their previous teams have felt. The teammates of the leaver do not receive a "Win or Loss" in their match history. Call it something else, and no gain or loss of LP.
Also another thought, giving the habitual leavers an "AFK" or "Leaver" banner to show that they do this often, basically labelling them, I know society hates labels, but people in ranked hate leavers lol! At some point, just like with Toxic players eventually banning their account. Speaking of bans, I believe bans should be MAC address specific, not email or IP specific, keeping people who habitually break the rules out of league.
This post stems from 6 matches in a row having 1 to 3 players argue and be toxic and go afk or feed, instead of trying to work together and try and turn the game around or ff @ 20 if a loss seems inevitable.