Losing a game in ranked - Slight alternative to LP loss

When I lose a game where I performed poorly, I always feel like I deserve to lose and I feel bad for my teammates. When I lose a game where I performed really well, I always feel like it's unfair to lose that much LP.

What if, supposedly, the amount of LP lost was sligtly affected by the grading system. For exemple, what if it went a little like this: LP loss increase and decrease based on rank (S, A, B etc...) from the grading system received after the game (based on the LP loss the player would of normally received):

Best rank : -25% LP loss 2nd best rank : -10% LP loss 3rd best rank : no change 4th best rank : +10% LP loss 5th best rank : +25% LP loss

I feel like it would encourage people to try their hardest, further punish int. feeders and trolls (over b5) and make every game's LP change a little more accurate to the actual player, while still keeping this a team game by still losing LP when you lose a game.

Is the grading system good enough to put something like this on it, or is it too unreliable or unfair for some roles (harder to get a good rank in some roles)? Thoughts?