MMR Feat...AFK,DC and the INTENTIONAL FEEDERS etc..

Why does our mmr still run off of wins and losses , i think this is out dated now that they have grading system after each game. The majority of my losses in the last 3 days are from players who AFK,DC or INTENTIONALLY FEED, why cant RIOT make it so the "MMR" system or whatever you wanna call it. Runs of the individuals grade after each game, instead of wins and losses. I do not think its fair and i know its not fun, its F-ING stressful and unnecessary. To get to the point where you have 5 games in a row where someone does one of these things to ruin you game and your MMR, to the point your looking at demotion. It makes it very hard to get out of these rankings when you are not one of these players that AFK, DC or FEED ON PURPOSE. Like i am struggling to keep silver again i was silver 4 three days ago, i have already climbed to silver 5 twice now if i get demoted it will have to be a third time and that is ridiculous, and this time it is due to what i have been talkinga bout here, all this in 3 days.

RIOT FIX THE MMR SYSTEM (or whatever you want to call it)