To be totally honest you don't need any at this stage. You just need a competent and geared raid group. Don't stack a bunch of caster DPS or duel wield melee as they suffer the most DPS loss from her debuffs. Make sure your healers are on the ball and able to communicate unchained magic so they can cover each others raid assignments and you got yourself a kill.
Overall just by simply executing this fight properly is how you defeat it.
There is something so appealing about backhanding someone across the face with a shield.