I never understood why the bow was restricted to Huntsman. Mercenaries using bows are commonplace in the lore, and I don’t know about nights, but I’m sure it’s not any worse than giving him a blunderbuss. Being OP isn’t a factor since it really isn’t that good of a weapon without Huntsman skills to buff it up.
But honestly most of the career-specific weapons don’t have a reason to be so.