I play MCH a lot as my choice of DPS but to name a few that annoy me would be the rng combos, the bullet system, and the level sync problem.
having cooldown to keep the bar from overheating while having the guass round in between skills feels good to me but when you get level synced you start to find managing the bar from over heating is a big problem.

I could forgive most of the problems with the other skill if just those skills could get reworked in a way