We all know how frustrating is when you have afk in you game, and then you are stuck in 30 min long game with no "future" waiting to lose and your team is flaming each other, and you can't do anything, but if you go afk and wait util game end you will be reported for afk :) I think this is good suggestion about that problem.
I think If you have Afk in your team that is afk for more than 7 mins, you can simply leave game and that will count as loss prevented, BUT to counter Duos that work like "I am in promo if we start losing you leave, and I will leave when uit happen to you " Guy that leave get 1 day ban (10time)-for Ranked
and normal 5 games in low priority for normals. it would "restart" on end of season.
If player leave more than 10 time in one season, He would get 2 days ban(10times) and then 4(10) 8(10) and like that.
P.S don't kill me if I made grammar mistake I don't speak English since I have been born :V