I'd concur with Notorious. Speaking from experience, WW Monks were strong. I can recall a few fights with them. I had a 1v1 on my Ret Paladin with one outside of the ruins in the north-western part of the Vale of Eternal Blossoms. This was probably in early Throne of Thunder patch, I don't recall exactly. I could manage to drop the guy fairly low, but he'd CC me, run away behind a pillar, and heal himself - for quite a bit. Then he'd come back at me. Due to exactly that is why I lost the fight against him, because even as a Ret Paladin, I couldn't keep up with his sustain - he wore me down.
Then later, in the Siege of Orgrimmar patch, I recall doing a 2v1 against one on the roof of the Stormstout Brewery. Me on my Ret Paladin, and a DK friend (I don't recall his spec). I don't think we managed to kill the monk, he kept getting away and healing himself behind the chimney(s), and eventually got out of combat long enough to mount up and fly away, iirc.
Playing my own Mistweaver, I do know that Xuen was capable of some pretty decent burst DPS. That is what the talent is for, after all. It is a damage CD.
Those are just a couple of my experiences. Point being, they are strong if played properly. Does that mean they aren't bugged on here? I don't know. I will leave that up to the QA team and the developers to decide, or the players who have experience with them and make good reports on the bug-tracker. What I can say, though, is that even if they were to be 100% working correctly, they will still be a pain in the backside.

