DRK freaking sucks for AoE simply due to the fact of how much more complex it's become since HW. Back in HW you turn off grit and spam DA-AD and sustain so much because you did tons of damage.

Now? You better forget about spamming DA-AD more than twice or else you have to wait until your mana refills or wait for TBN/quietus, or god forbid actually have to interrupt aoe for syphon strike spam.
Also, to that comment about WAR having weaker AoE due to TP constraints, do keep in mind steel cyclone/decimate/equilibrium exists. Plus, there's a good chance you'll have a caster/melee comp, meaning you can tell that smelly good-for-nothing dps to at least goad you.