Heh, it's an idea, but it doesn't really add realism, and we're in a fantasy setting...
So, let the vampire be as he is, as Knight said.
Don't go overboard. It's fantasy, but everything needs to be within reasonable limits. Would you make a gnome a giant?:rolleyes: After all, according to you, everything is fantasy;) .
The developers will never make a vampire with a bow. Because then, who would buy such a game? And Ubisoft would smack them on the head and, most importantly for them, cut off their MONEY.