oh also, to the OP's assertion..
So far, i've had SOME trouble in instances with AoE threat, but mostly because this game so far seems to have a preference for giving us big packs of ranged mobs that are really spread out. That seems more or less the issue than anything else. Frankly though; those ranged packs are usually non-elites so its not that big of a deal. The boss fights with add packs can be hairy but I always tell groups to ignore the adds and focus the boss until i give the word that its okay to attack adds. i usually have my healer stand behind or next to me.