I'm gonna put this in words that disregard professionalism but convey emotion.
Your matchmaking system is full of ****. IT'S ****ING WORTHLESS.
here are some suggestions:
-Get rid of Elo. it doesn't work.
-Replace with a system that looks at more stats instead of a number based on win/loss ratio.
-For example: pick champion before queue and the system will put you together with a team depending on what you choose. Shouldn't be too hard, after all, you do have one million players. I'd rather wait an extra minute than commit to a half hour of painfully trying to tell some guy stop doing such and such.
-Take account of personal k/d/a ratio for each champ. If it deviates from the ideal ratio, (1.5-2/1/1 for carry, 1/1/2 for tanks, you get the idea), then the player will be matched accordingly.
-Make ignore list also ignore players for matchmaking.
-This whole carry-effect, feeder-effect is not acceptable analogy. Every game I have had today was full of people that didn't know how to play. I would be pushing after killing four people, they would be going around chasing the guy that was alive. Then another time, they aced us and didn't push, so I told people after re-spawn, check baron. Guess what? Two of us went, lucky for us only three enemy were there. We stole baron, but the rest of the team proceed to go and try to fight their whole team 1v5. Put it simply, I don't want to be 40% of the ****ing team. I don't want to be 21% of the ****ing team. I wanna play, I wanna have fun, and if I lose, I want it to be for legitimate reasons like we were out played. Not that the enemy made less mistakes.
On another note, pvp.net is a piece of ****. I'd rather pay $30 a month than put up with this thing. So give me another option.