Sometimes i'm doing real good but my garen top fed that Triforce Darius into oblivion and theres nothing I can do. So if I do really good but still lose, let me lose 10 lp instead of 17, only solution to torlling teammates
All that will do is encourage KDA players and deter them from actually trying to win.
but on the flip side it encourages extremely greedy play.
example, my botlane already died 4 times, so im going to literally not participate in any team fights to attempt a comeback, despite my mid being fed simply to preserve my KDA and therefore LP.
at the same time, i would try my absolute hardest to get gold dumped onto myself by KS'ing allies as much as possible to increase my gains.
you've also got champions like 
where it is generally easier to increase KDA without actively doing much to help, therefore their mains kind of gain inflated LP gains, which is kind of unfair.
I would be ok, as long as the winning players with a bad contribution also win LESS LP for the win they don't deserve.
From my perspective. The worst person on wining team and best person on losing team should get 0 lp win/lose. To equalise and deter people from being burdens and baggage
