I also see the potential in the concept but I'm not happy with the design.
Why can't you do a hamstring shot with a crossbow? It's just aiming at someone's feet. Why can you only do it once per Short Rest?
3e had a better design for Pinning Shot with unlimited uses but with an attack penalty. If you need to tactically restrict the mobility of a certain type of enemy, or one overpowering enemy, you need to be able to do it more than once for it to actually be a tactic.
It doesn't necessarily have to be an attack penalty. 5e even offers the perfect tradeoff without having to resort to making you miss more. Bonus Action. You could spend your Bonus Action to add an effect like movement penalty. It would make perfect sense to lose a Bonus Action for taking longer to aim. And Bonus Action would always have a use. It's win-win. Perhaps throw in a Con save to keep it balanced.
Then there are abilities like Mobile Shot that feel much more like a character ability than a weapon ability. Holding a bow doesn't turn a clumsy heavily armored fighter into a nimble Rogue who can do running shots.
Last edited by 1varangian; 03/11/21 02:44 PM.