First off..... You were DPSing. Aka, you should be taking minimal damage. You could get away with DPSing naked except for the fact that you'd lose out on bonus damage from power armor. Now if you were the one doing the tanking, you'd probably struggle in Pernix until you got used to tanking. As for ROTS, you need Superior Elite Void or Tectonic/Sirenic to be accepted on any decent team as well as t90 mage/ranged. The thing about ROTS is that they gank you regardless of what kind of armor you have on, so its power armor or bust. You might be able to get away with normal void or Nex sets if you go with friends...... As for your Pernix set, I'd say sell it and buy drygores with that money if you intend on doing more nex. Just melee Nex instead of using t75 mage. I personally use Pernix to do QBD in since it offers more defense than Armadyl and better damage bonus.