Make sure you're 3 healing it. "Relatively easy learning curve" is an understatement, considering my guild one shot this boss having never seen it before.
Same thing. No troubles what-so-ever. Yes the AoE dmg is something when noone is up, but just stack for aoe heals and keep pulling strings ready for people on the topside so they can get up asap. Seemed to be the easiest fight in the instance aswell.
make sure your using cooldowns, taking a look at your paladin he only cast aura mastery once (looking at your longest attempt, #12), and he never cast divine protection, which is on a 45 sec cd and if glyphed (which he should be) reduces all magic damage by a significant amount.
Also, the Tol Barad trinket still works here, so if too much dmg is a problem, yous hould have your raiders pick it up (if they haven't already) and use it during the AE phase.