Here's a balance related issue:

Stop "balancing" me with players far lower than my skill level and expecting me to carry the game, then punishing me with a 23 lp loss for it when my effectiveness in the drastic majority of the games is strikingly 2/3rds of the team's fight. But that's irrelevant. I don't appreciate losing 23, then only gaining 11-15 for a win. You waste my entire day (weeks at a time), working hard for a gain, by screwing me in this manner. Balance the game by balancing the lp gains or balancing the matchmaking to those of your actual rating. MMR? I haven't any idea what you do with this, but this should not be a thing. Some players spam ranked games with hyper carry champs all of the way to diamond. Me? I play trundle, kennen; champions that require a strategic amount of watching your team and positioning to make plays in the bigger picture. Extremely useful, very effective, but not save the entire game by yourself champs. And while my effectiveness, personally, is stellar, it's all but ignored in the formula's assumption of my skill level.. when you're blatantly screwing my appearance on it by matching me with people rated far far, effing shittons lower? Figure it out. This has been going on for years.