Originally Posted by
DarkwingDuck
The problem with Versatility as a healer stat is that the damage reduction part of the stat only affects yourself. This means that it has greatly reduced value from a healing perspective, as the amount of overall raid damage it ends up reducing is miniscule.
Personally, my current stat priority looks like this: Intellect -> Haste -> Mastery -> Multistrike -> Crit -> Versatility.
Versatility is simply far too expensive on the stat budget for what it gives you. Like you wrote yourself, Versatility requires almost 48 % more stat points for 1 % increased healing compared to Mastery.