for me... the raid need 2 affliction lock and 1 shadow destro (with balance dudu in party).
with at least 30-35% crit rating raid buffed (and 16% hit rating) on boss fight you can take up che Improved shadowbolt for the entire combat. It means +20% damage for affli lock and shadowpriest (and boost personal damage by Curse of Agony or CoD) and affli lock take up che improved curse
