Reward individual player performance with slight extra lp/mmr gain

I always hated how everyone in the game gets/loses LP relative only to their mmr they got from winning/losing regardless of in game performance in that particular game. Of course gaging every players true impact to the games outcome could prove to be very difficult although I actually think that the current rating, going from s+ to d, is quite good. If you think about it this takes into account several things,not just kills, all of which are very indicative of performance level; farm score,wards,wards cleared etc. I believe this is usually a good indicator of how impactful the player has been. You wouldnt have to balance the whole lp gain around this maybe just reward players who have done exceptionally well with as little as 3 to 5 extra LP and mmr (or even smaller) and make that 0 10 lose 5 extra. People would now be more careful not to go 0 10 where currently you sometimes have to think that they stop caring completely after already dying 3 times even though they might still turn the game around ( with the help of their team) So whats the point ultimately? Say a 20 3 who outclassed her lane opponent by a lot and generally played exceptionally well still couldnt make up for everyone else on her team getting outclassed so she loses but also gets a slight lp bonus for permance which obviously cant cancel out the loss but makes it so only 11 Lp are lost instead of say 16.At the moment these kind of games are very frustrating for good players on the losing team. This would then allow players who do very well individually to advance slightly faster even when losing and would push players who consistently do bad out of the respectives division slightly quicker. Of course there might be ways to abuse the current rating system and there are a bunch of other problems like games where one team agrees to surrender early possibly leaving all of them with mediocre performance ranks because of the time they spent waiting for the enemy team to push mid. Right now there are a lot of games where some players simply appear to be a lot worse than everyone else often times making the game impossible to win for the team unfortunate enough to have that player on their team(I suspect this has to do with the fact that duo q ranges are too high as well, sometimes its golds plats and even diamond 5s in 1 game without their being smurfs.) Sane players would very rarely go 0 10 and know how to correctly play from a deficit without further feeding their opponent and if players do that (referring to mindlessly feeding) regularly they should get demoted faster than their teammates whose time they wasted. This should only apply to exceptionally good/bad performances so the majority of players in a game stay unaffected with only the carries (supports can get s+ too btw) and "feeders" noticing it. (not english so I hope all is understandable, tried to structure it as best I could.) Also riot has most likely thought about this themselves already but then decided not to include so there must problems, too big, keeping them from putting it into action.