it's overrated. 8-9k hp is enough for raiding. mana ftw instead. means less tapping.
What class is it again that can refill your mana bar mid fight? Ya thats right it is Necos, crap that was DAoC. So untill i always have a Vampiric touch Priest or a druid(and think of what a waste of innovate due to low spr) in my group, i will keep using DP or Imp Life tap to get my mana.