We ended up killing it (3 shot) by running just the Rog for melee and having him handle soaks. Swapping to ranged-heavy made those orbs soooo much easier. As we get more gear/more familiar we will probably rotate the melee in for kills/loot, but for now, ranged is beast.
Not sure I'll ever tank it though because of....
This. This makes me a sad I hate that "gonna cast this now, unless I don't feel like it! trololol" ability.