Aren't Shadow Priests the worst at AOE right now? Also, on trash, if you're not Combat as a Rogue, you're not going to be doing a lot of AOE DPS. So, a 801 WW Monk out DPSing those isn't saying much. Out DPS Havoc Demon Hunters, Combat Rogues, Hunters; then we can talk.
Personally, what I find way more surprising is Arcane Mages. I had one in my group today and he gets to do 500k DPS by spamming Arcane Explosion. Now, I know Strike of the Windlord is overpowered, but as a WW Monk we have at least 7 abilities we need to use during AOE to be effective, further complicated by our mastery, the Hit Combo talent and Spinning Crane Kick, while an Arcane Mage only really needs 3 at the most. Is that fair then?
Also, Frost Death Knights, who used to be king of AOE DPS, are useless. Single target is even worse. I really wish that, instead of worrying about the OP classes, they woud look at the weak ones first. Certain specs are just plain bad and will never be taken in a Mythic run. WW Monk AOE burst is ridiculous, but it doesn't hinder our gameplay; it does for others, which is a far greater problem.