(Again, sorry if this is a dupe. I crashed again (3rd time) submitting a bug).
Given the increased difficulty of mobs, I think it will be hard to test much of the game. Server populations just don't support larger groups, and .aggro off doesn't help if the single mob you need to kill squashes you and your healer like bugs. I think you'll need to dial back the difficulty if you want a lot of things tested.