It has been nerfed to 3 stacks and 35% on each. However, mana cost will be reduced by 35% on each stack as well, I think prior to the patch it did not reduce mana cost. This will be a go to for ret as it doesen't consume holy power or force you to use WoG to be effective. Also the mana reduction and mana cast reduction effect is viable on yourself. The percent healing increase of the spell is still only applicable on other people.