Parry is good when you speed run or undergear the content you doing.

as you gearing up, parry start to lose it usefulness. (T9 ilv110 max parry will mostly lead to Over Healing in most case.)
most end game healer that I saw will pre-cast heal so it hit the tank right after big atk. I never saw end game healer wait for tank to take big atk then decide which heal to cast.. just so they can use cure1 instead of Cure2 ;P