Alas, our survival hunter had connection problems all night and some of our attempts suffered as a result. In saying that, I have a couple of things to help you avoid wasting attempts needlessly.
1) On the first pull, your healers need to know that the abomination appears (at least on Grid) as a debuff and can be dispelled. Yep, our priest kept dispelling the abomination every time the off tank possessed it on our first try. Oops.
2) The adds seem to alternate, and the green one is where you really have to be on the ball. We started handling it by moving to the opposite side of the room once an add had gone down, giving us maximum time to bring it down. In addition to that, your ranged people should feel free to go at it right away as, even if a ranged person is picked, you have time to react and the extra DPS is really helpful. If your abomination is on the ball, he should also help with bringing it down.
That said, we're back tomorrow night to finish him off in our last four attempts. It's an awesome and perfectly tuned fight, as they all are in the Plagueworks, but I'm pretty confident.
Unwavering Sentinel: Tales of a Protection Warrior Running Wild.