You shouldnt try to stay inside his static tornado too long after he jump on you since he can do some "balanced" damage while being invisible. I only fight him with batsin and the pattern is : charge coupdegrace with ghost -> get close to boss -> boss offensive tele -> release coupdegrace ...
Elemental pierce from gear work on traps. The reason it seems doesnt work because the enemy maximum negative resist is -99(or -100) and average mobs has 35-40% resists, so having more than 135 doesnt do anything.
When you alnost at the end of lap 1, summon edyrem far forward. Then right after he pounce you, run away to pass that edyrem as far as you can. He will pounce him instead of you.
Im pretty sure claw give less frame and psionic storm easier to clear traps. Twinfang for mobs.