To be honest, connection issues, (whether it be genuine connection issues or people figuring out a way to cheat) and the amount of kill trading that goes down. I shouldn't hear my character punch an enemy, watch them die, then after they die, hear them punch me and I die as well... If it weren't for shit like that, I think destiny would be some of the best FPS multiplayer I have ever played. They also seriously need more game types and give us custom matches.