Niuzao isn't too bad once you get used to it. The first boss is easy, I tank him over to one side and swap in and out of the growing amber pool with whoever is there. I send my melee DPS off after the oozes via IWT and back again.

Vo'jak is a PITA because there's a lot going on. Dropping the tar bombs is a rather big distraction so I don't get too caught up in them. I set my healer up on one side and let her drop some when I have time, and I do some on my main when I can, but I don't worry about dropping as many as I can, a few is enough to slow them down.

DPS the melee guys {wave 1 and 3} as they come up, avoid the bombadier {PITA}, don't IWT too much or you'll run yourself off the wall {sucks}. The second and 4th wave, where you get the explodie guys, I make sure to drop a few tars to slow them up and just stand on the edge and hit them with ranged attacks {Shield, Shocks, Judge, whatever's up} and let them blow each other up. One shot is all it takes.

When you finally get to the boss, it's a crapshoot how many guys, if any, I lose. If someone dies, I go to the opposite side of the platform. Sometimes he'll do his jump and spin on a corpse or on my totems. If no one is dead, I'll leave my healer at range and expect her to get jumpspinned. If you've got enough gear you can try healing out the damage, if not, strafing out. If you're really lucky and he's jumping on a corpse or totems or something, you can position near the leftover tar bombs and throw those at him when he's spinning to clear his damage boost and do some decent damage to him.

Pa'valak is pretty easy. Avoid the blade rush, which gives plenty of warning. Heal through the tempest. When the barrier is up, use AOE and use the bombs with your tank. Don't chase bombs, by the time you get to them, they're going to be ready to explode. Just wait for them to be relatively close to you and try to position so you can hit him, his shield and most importantly the ads. the ads have a pretty brutal stacking DoT, so you want to kill them off asap.

The last boss is a bit of a PITA but not difficult. Stay out of the puddles. Jump to clear the Quick-Dry Resin, don't spam IWT or you could fall off the bridge. As soon a he starts to take off, start running to the other side of the bridge. I generally dump my slaves against the first barrier {as long as they aren't in a puddle} and chase him down on my main. Hit him with an interrupt when he's casting his winds spell, go back and grab the slaves you lost/left behind, rinse and repeat.