Edgewalker is right though. WotN is completely reliable, and hence just the strongest tanktalent you'll find in the blood-tree.
A tree built around taking the full damage and then re-healing parts of it to cushion it all of a sudden gets a very powerful and completely reliable damage reduction. It is that powerful.
The real issue is that they made it too reliable. It was ok as long as it wasn't, because then the concept of the Blood tree was still to take all damage and heal it, at times if you fail, your talents may save your hide anyways. Now Blood is about taking less damage than Frost or Unholy, does that sound weird to anyone else, too?
-- (The Death of Rats, Terry Pratchett, Soul Music)