Well, my Demon Hunter is in Act 4 Hell now, and feels pretty op.

Smokescreen with prolonged duration rune plus Preparation with Focussed Mind rune makes you pretty much invincible for 30 to 40 seconds out of 60.

You're unattackable, you don't get any damage, you can brake snares and roots with it, you can even get out of the Butcher's hook.
And if that weren't enough, you can also do full damage while smokescreened.

If this makes it to PvP, DHs will destroy everyone.