I was going to make a point how the huge cost is probably a throw back to Blood dps days, but then I noticed I couldn't actually come up with any decent justification for it even back THEN. Maybe forcing a slight ramp up time for PvP? Anyway, these days the 60 RP cost is completely asinine. 60 RP isn't just 2 Rune Strikes, it's 4 Blood Tap charges which in turn is 0.4 Death Strikes etc etc. It's a nice enough cooldown in that it provides both damage and damage reduction, but honestly it's not particularly powerful in either aspect and the huge resource cost just adds an additional layer of "meh" to the ability.