Why aren't LP gains given the same way we do Champion Mastery?
Your LP gains should be about your average skill, not about your team's skill.
My LP gain shouldn't be relative to how the 5 of us came together and won. It's supposed to be about me. My standing is supposed to be relative to me. I'm not trying to be THAT GUY about "o wat if u get matchmade wit 4 shitt playrz?///" but it should be about me. Both the positive and the negative. It's entirely possible for me to get carried to victory by going 0/7/0 and buying 6 tears on Katarina, but the LP I gain will have nothing to do with how shitty I played.
Similar to the formula for champion mastery. It's an average of kill participation (kills/assists), deaths, gold income, objectives taken/participated in, wards placed/destroyed, etc.
Obviously make it so you can lose LP still, but this way even if you lose a game there's still potential for you to lose less or even gain some depending on how well you did as a personal player.