Champion mastery and the Ranked system

EDIT: You guys do realize I'm saying that the amount you get or lose is effected not whether you are gaining or losing

In the comment section of another thread I just had a troll telling me it unfair that some people who get fewer kills then him are ranked higher. But thanks to that troll I realized something that seems to be missing from ranked.

Right now the LP you gain or lose from a game is based solely on your mmr compared to the mmr of the people you faced(possibly the mmr of your team). But it doesn't take into account how you actually performed in that game. You could have fed your ass off or carried hard and you would still get the same LP. Wouldn't it be nice if there was a way you could be rewarded more or less based on how you actually performed. Oh hey, there is the champion mastery score that gives you a grade based on how you performed ...

Would you want your grade to effect how much LP you gain/lose?