The new T7 4 set bonus gives you 300 spirit for 10 seconds when you lifetap (which turns into 90-117 spell damage from fel armor depending on if you talented it or not) and +1200 extra mana from lifetap.
Seems like an interesting mechanic to me LT will now likey be in our raid rotation, and we gain vastly increased mana return while chain tapping.
Thoughts?