The first 30% or so of this fight is a DPS race to get past the crystals/adds phase, when the first 3 spawn, pull them to your tank and ae them or assist burn them down and get back on the boss asap. As mentioned above, she casts a MELEE ds on her as soon as adds spawn, so you need to dispell this AFTER the final add is dead, if you do it before, she just puts it back on. You can avoid this DS by using Casters.
The crystals you should only get 1 set of if your group is bringing enough dps to the table and working together, you want to destroy all 3, but as mentioned above you can survive with less. The longer this part goes on, the more staggered the adds/crystals become, sometimes spawning at the same time. It's likely you'll be overwhelmed here, this is why you burn her past it.
When she goes into Decay mode, the dot mentioned above has to be avoided by going into the blue aura that randomly spawns on the pools around you, it seemed to be about 12 seconds from spawn to pooing ef, and you have to stand in it until it goes away (it will protect you from getting the DoT) If you have enough dps, you can entirely skip this phase by burning her down Very quickly.
I want to say around 50% she started spawning her Mini bosses. There was a ghoul, a skeleton sentinel, and something else. They always come in the same order, and so far are weak to the same aura every time. When they spawn, you have to drag them to the appropriate aura to be able to damage them, The first was South east, Go clockwise from there. These mini bosses aren't much to deal with, If you only have 1 tank, you should be okay, as Anashti seems rooted/inactive in the center during this phase.
All mini bosses down? Use whatever burns you have left, it's tank and spank from there. Keep your group's health topped all the way off as there is an AE that will continue firing off but you can fight through it no problem.
The loot is the same as all the other missions so far - LAME!
Currently /bugging the Poison blast achievement, it has not popped for the groups I was in or communicated with at least 4 seperate times with No deaths during entire fight.
Cazic.Xenthoxin, Best of luck everybody.