I am a Demo, Arcanist. Using Flamestike and the two different buffs as my really only skills. I am mowing through normal. some good gear and it rocks. (using dual guns)
http://grimcalc.com/build/4DHMoW is the skills set I want at 85 (no clue if it is viable at higher difficulties.) Also dont know if i can have both end arcanists abilties i think both are specail and only one can be active at a time.
My damage is pretty much all over the place so i dont tend to end up in a bad spot due to 1 mob having a super high resistance (though Fire damage is pretty high up there.)
Devouring Swarm and Grasping Vines alone can give you all the aoe you need with a bit of devotion support. Or Primal Strike for that matter (probably, haven’t actually used it much). So aoe isn’t a problem for a warder.
I vote you go Sorcerer. Either Callidor’s Tempest or his little sisters of the poor Black Water Cocktail version. Either way you become a GOD of AOE.
This is my BWC Sorcerer http://grimcalc.com/build/d12WLg