Determining LP gain/Loss

Riot needs to make a system where losing and gaining LP is more than determined by a loss, win, and MMR. It should be decided by the grade you get in your role at the end since those are based more on stats within the game. It is annoying to lose a game after earning an S. or being 2/2/20 on a support but losing a great deal of LP. It isnt fair for ranked gain/loss to be solely wins or losses because the match making is never truly balanced. Even though someone is the same rank as you doesnt mean they are of equal skill. (low elo) a fresh 30 can do ranked and get placed silver 5, but someone could be playing for years and be silver and smash that new player in lane.