Ranked LP Gain and Loss (IDEA)

While sitting idle in my chair the other day, I was thinking, what if LP gain and loss was influenced by grade (D through S) on top of if you win or lose? This way, if your team feeds but you do well and win your lane and try your best, ending with an A or S, you could be rewarded with a lesser LP loss. And if you do bad, say feed due to lack of experience or not trying, you get punished for your bad score with a higher LP loss. This could encourage players to try harder and play the game out. It would also sort out the newer/bad players to a more suitable rank if they are paired up in a higher ELO and play sub-par to the rest of the group. Maybe you could have a slight LP boost if you win (2-5 bonus LP) if you win and end with a high end grade. I get tired of games where I do well (A or S) but my team ends up feeding the enemy and I get punished for it, this would hopefully provide some sort of resolve to an annoying issue that I'm sure at least a handful of players face.