My raid killed this boss for the first time last night; First off, my raid base consists of only 10 players, we raid 5-6hrs a week, we 2-heal everything so far (3rd healer for harder heroics later)
I modified a few of the tactics to make it easier for our comp, could be helpful to others
Raid Comp - Healers - 2 (Druid/Shammy) Tanks -2 (DK/Feral) Mellee DPS - 2 (Rogue/Warrior) Ranged-4 (Priest/Mage/Lock/Hunter)
Things we did that made it easier for us;
- Interrupted as many "Sha Sears" as you can when not during the "Desperate Measures" of Rook and getting the "shocks" have your ranged focus him and get a tidy rotation, really helps out a lot with only 2 healers
- During "Sun's" Desperate measures we cleaved off the large add on the outside. Only aoe'd if there was lots of adds up, we found the focus damage faster
- Used "Lust/Heroism" on first Mark of Anguish phase and nuke him as hard as possible. The first fixate going to the rogue, then passing to ranged (we set up a rotation to make sure the distances where maximized)
- Saved our personal DPS cooldowns for the second Mark of Anguish phase again to burn as fast as possible and get out of that phase.
Not groundbreaking changes, but really helped us for 2-healing it.