When I was attempting him it seemed fairly doable, but the biggest problem I had was killing burrowers fast enough to get some good dps on anub (491 ilvl). With a little more gear p1/p2 will be easy enough, but then it comes down to p3. Best bet is probably going to be to LT to low hp before p3 starts and pop all your CDs as the phase starts. It might also be useful to spec into sac pact to help offset the dmg from pen cold.
---------- Post added 2013-01-26 at 11:51 AM ----------
Also harvest life helps out if you are a little low on gear and are taking a lot of dmg from the whelps.