Coup de Grace perk

It has somewhat potential but very limited usage and not being able to use it whenever you choose makes it a never-equip perk. It is too unpredictable sometimes I don't want to use it but a semi launch gets away from me, wasting one of only 5 usage perk. Either it should have cooldown instead of 5 gen condition or it should be more like Dead hard needed to press a button to activate it.