The problem I have with this is that the player doesn't know how many hit points the orc has or what that force's capabilities are or anything else. The job of the GM is to give the players information they can use to make meaningful decisions. In the case of combat, that includes things like telegraphing effectiveness through description. When I GM, a description like "You stab the orc in the neck and blood gushes out like Tarantino directed this scene" means you just dropped that orc to nearly dead. The player is literally incapable of determining that (unless the enemies' HP are "visible") so it disrupts the flow of information from one side of the screen to the other.
I'm not saying that players should not apply flourishes to their descriptions, just that results are necessarily the purview of the GM in D&D and most other traditional RPGs. There are games that support player driven narrative, of course, and many are a hoot.