Just because you may not parry a lot in a fight doesn't mean you won't always. When tanking a boss like twin with slow predictable hits, parry isn't amazing. When tanking a pile of guys like turn 4, it really adds up quick. I see the argument that extra dps from the tank may help push ahead of enrage timers but really that just says your dd group is undergeared or not performing in the encounter. Just because you can beat Levi ex doesn't mean you aren't below the level it is tuned for.