Even after CC they were still overtuned, hence the sequence of nerfs they got. You had individual enemies with ridiculous burst, and some of them couldn't be CC'd.
Then when I said "the entire of Arcatraz" I was also referring to the doomclock mobs (good luck with those in dungeon gear) and several of the bosses who also got nerfed. No it wasn't impossible, but it was sure far more difficult than any 5 man before or since.
Also DA has a use at Skulloc if you want to get back to him before the second bombardment wave.