Given the issue currently with healers I was thinking that there could be a way to change the way Spirit works, well replace it really, and simple keep the ones like Critical Strike and Haste. As it stands Mastery usually helps healing output so aside from broken ones it shouldn't need a change. So what about the idea that either stat could be linked to how healers get Mana returns. Something along the lines of:
Critical Strikes return 30% of the base Mana cost
Haste returns a static amount of Mana per 5 seconds like it does currently for DpS. Scale it accordingly.
I just thought this could remove the issue of Healers needing different amounts of Spirit. Hell it should also help the curve of gearing given when you get better gear you scale pretty well as your regen should increase as the challenge does.
Any thoughts?