Just wanted add some screens
http://imgur.com/fB4coPd
http://imgur.com/d2SKVF0
Bascily Anub and noth hit tank for 25k all the time. Not once or two times in whole fight, basicly every boss hit take 80-90% tank hp. Sometimes even more. And to be clear, this are normal boss melee hits, not even crits, skills etc. Sometimes Anub double swing hit tank with def cap for over 35k.
yes yes some will write tank need to learn using CD, learn timming better, sure. But there is simple no way that both tanks will have enough Cd's for whole fight ( every of our dps was making 5k+ dps which is enough for naxx 10, even buffed one) . Or you gonna write healers need learn to heal, we kept tank on full hp all time, but he was one shotted anyway in random phase of the fight.
They simple took naxx 25 dmg and put it into naxx 10 or what ?:p
Ps. We did same bosses like 2 days ago without any problems. Damage changed after todays PTR restart, like 2-3h ago.