idk, im personally thinking of taking improved devotion aura purely for when a resto druid is not available. From what ive seen videos of, tankadins are just fine on threat not using ret aura, so dont really see why not taking improved devotion. 6% more healing to the raid is just godly. Reminds me of when i used to be 38/23 holy / ret not for shockadin, but just for the improved sanctity aura for bonus healing.