I don't really believe that is true. Because I play Team Slayer w/ my friends all the time and I'm better than most of them. You say all it takes into account is wheter you win or lose but a lot of times I get MVP and my skill is always going up but then my friends that do bad still get a win but don't rank up. You can see that each player is ranked on their individual skills. We played basically the same amount of matches and obviously would win or lose the same amount but the better players get a higher rank and the worse kids don't really rank up.