Directional shield blocking

I think it would be cool if the shield would block depending on where you look. If you were to look down you could block the teeth from evokers, but in exchange you could be attacked from infront, or if you look up you could block an attack from a mace, drippstone and other things. I under stand that this could probably be considered op so maby in return you could only block so many attacks untill it has a cool down like with how the axe disables shields in Java.