Definitely not in CoD, because if you can't kill someone running at you with a knife in a game where three bullets to the crotch is a guaranteed kill, you deserve to die. And if someone sneaks up on you with a knife they could have just as easily shot you and it would yield pretty much the same result. Maybe in gears, because you have to unload a whole clip into your enemy before they go down, but gears is really unbalanced anyways, being as they start you off with a power weapon. But if you don't count the shotgun as a melee weapon then it's debatable, because you can stop a lancer with a shotgun fairly easily.