A system that rewards individual performance
Even if you play like a god and go unkilled the entire game if you lose then you lose.You lose LP and nothing else is gained. Riot should introduce a system that rewards players for good individual performance such as a strong kda or cs/min. These rewards dont have to be big maybe just gain a little more ip or lose a little less LP. This way a least riot acknowledges that you did well and the game doesnt feel like a complete waste of time. This also would compel players to improve and maybe make the community less toxic.