They are a serious pain, I just burned them down (popped bestial wrath, arcane, multishot, everything) and stunned them with intimidations/war stomp, along with heavy healing on the war and pets. I wiped at least twice to them anyways though, the worst was when a patrol of dryads hit me while I was fighting a few of these guys, that poison-slow is just evil.

I would probably kite them backwards towards the instance entrance if I got more than 2, maybe 3 at a time.