Guess why? It's to make more toxic players, it's the rito logic...
-25 LP if your teammates FEED SO HARD making you lose and +16 LP when you win, at this rate i will FCKING reach diamond from silver when 
get his "relaunch".
Lane performance isn't everything. There are some people who's laning mechanics are exceptional and they lose lane maybe 1/20 games, but they have no idea when to teleport botlane, where to ward, when to roam, how to teamfight etc. There are people who are terrible at 1v1 and often lose lane, but know exactly how to teamfight, how to rotate, enemy movement prediction etc.
However, I have found that the champion mastery grade is quite accurate regardless of what your playstyle is, and LP gain/loss should be based at least somewhat on your grade.
lol. Performance in a match has absolutely no effect on LP gain or loss. The only thing that matters is MMR.
High losses and low gains means your MMR is low for your division.
