I think it really boils down to how much the player WANTS to improve. Perhaps the best example I can think of was a newcomer, Irastorza, to Miami. He was predominantly all left side, but a beautiful left side. He could catch on the forehand, but the return was rather weak. Well, now, look at him. The transition was terrific. Who knows how he did it, but whatever he did, it truly worked. If the players were on a worldwide stage, like most pro sports, they'd be forced to learn, but it's a different, narrowly watched sport, unfortunately.