It does make shooting more difficult. Depends on the trajectory of the ball, although this does not exclude you from shooting. A big's ability to hit an FT is typically a solid sign of the type of shooter he is. I believe that as people grow taller, they lose coordination, and some men never regain it. This would explain why most center players are also good shooters. Overall, being tall helps but isn't essential for making shots. There are plenty of short players who can shoot the ball well and vice versa.