They kinda baked every utility possible in offensive abilities and cds. So it sucks to fight them because at the same time they are kicking your face they are also mitigating damage. Sum that up with some huge numbers and it is just not fun to fight dhs, and some classes might as well not even try if it comes to a 1v1.
So, yeah, highly mobile glass cannons made of tungsten alloy with a skill floor generous enough that even an orangutan can play with success.
In arenas though, 2v2 or 3v3, it is still much worse to fight Rogue/FMage whatever. Yes, I know I play destro, but I have been here since BC, give me a break.