Coup de Mort question

[Lun]

I've heard that a coup de Mort can fail on an unconscious foe. Can this be changed? I find no reason that we can miss someone immobile laying on the ground with a killmove. I feel like a lot of people aren't taking this ability because it lacks a purpose. Quote Spearhead, "Why try a coup that might fail when three more whacks with my weapon guarantees their death?"

By unconscious, I don't mean a sleeping foe or an otherwise immobilized foe, but someone who's out of energy. I do admit that the ability to instantly kill someone who's asleep is not something a mercenary should have.

[Kent]

As an alternative, if the Coup roll fails, then a strike from the weapon hits and damage accrues instead. Not, the target gets off scot-free.