The major thing I'd like to see changed is the way mobs die so fast. It makes many things feel less effective like debuffs, combos, and crowd controls. An AoE fest also makes exping really boring imo. I'm glad they added exp chains/mob link, but it shouldn't be as easy as AoEing them down to get great exp. I hope they change this by raising the difficulty of each mob so that debuffs/crowdcontrols are required to handle a link of 3~5 mobs.

I think the diminishing effect of sleep is okay because you shouldn't be able to keep a mob slept forever. They should lower the reset time on the diminishing effect for some of the debuffs like paralyze, slow, and blind imo.