Would you agree that the face of the racquet at impact is what dictates the line of shot? If so, then from a neutral wrist position a player would primarily have to swing in the direction of the intended target. And as you most aptly put it, the swing is arching around contact.....in order to swing in an arc, the wrist would have to be laid back, or neutral, or anywhere in between to send the ball to different quadrants. The newest information (brian Gordon, tennisplayer) suggests that the wrist is not really a part of the whole stretch shortening cycle but is positional in nature... That is, the laid back wrist at the beginning of the swing provides a player with a substantial joint range of motion to postion the racquet at impact congruent to the target line. In fact, he maintains that the muscles controlling the wrist are resisting (to a lesser or greater extent) teh centripetal force created by the rotation of the arm around the shoulder... So what Im saying is , that if you want to swing in an arc, and create angular speed, BUT want to send the ball out on different quadrants, the position of the wrist (in a kenesthetic sense) is key... You ought to read his article in tennisplayer..its really good.