I run less parry/dodge/block now then when I started kara and have no issues with NB. I take it from your post that you are losing the tank? Do you have 3 healers? What are they doing when the tank dies?
Just need enough health to survive the burst damage that he does. The tank should be keeping up SB and should be avoiding getting feared by stance dancing. You also may need to move out of the void zones or whatever they are called if they happen under the tank.