AoE isn't all that important imo.
Trash isn't so important imo.
And on bosses, it's not all that common. And usually you'll have your mages/warlocks dealing with that, while you just continue to dps.
Heck, even as a DK I don't get away from my main target that often just to AoE 40 yards further to the back. Generally a waste of time, because they'll be down to 50% once you reach them.
Overall, I don't see this as a bad thing, because AoE as a melee class on a boss is fairly gimmicky. Not very important.
And now I'm going to shamelessly promote the best metal band from Belgium.
http://www.youtube.com/watch?v=CUN3Wo-mBgU