Match me with people who have a similar performance.
Fuck MMR. I am BEYOND TIRED of being matched with morons who can't play the game to save their lives. It doesn't matter how well I do, since everyone else on my "team" is going to be feeding their asses off. Oh, you're 12/1? Well, mid has fed 10 kills to the ever so balanced Annie, who can now 1v5 and win, and now you can't do anything but watch as you lose.
So, scrap MMR. Create a new system that queues you with people who have a similar performance to you. Then, good people will be matched with good people, and good people will climb. Bad people will be matched with their own kind, and be inspired to do better, and stop holding people back.