I used to think that a tall player is more vulnerable to body smash. The target area for the body smash is larger compared to a shorter player. But having studied the bio-mechanics of the tall and short players, I concluded that a tall player can defend the body smash equally well, if not better. Two reasons. Firstly. the area of sweep from cocked and uncocked wrist is the same for tall and short players. It is dependent on the length of the racket (std. 68 cm). Theoretically, no difference in area coverage. Secondly, it is well known that the best body smash is to aim at the hip of the opponent. However, if your opponent is very tall, his racket is short relative to his height and limbs. Meaning to say his racket face is relatively closer to his wrist compared to a short player. Also, he does not have to lift his arm so high to cover his hip with the racket face. Less time taken, better defence. You will notice that in table tennis where most of the shots are coming at your hip level, yet most people can defend well, just manipulating their wrist using the short bat. Remember I said everything else the same.