rafa said a couple of days back that he doesn't like hitting too many backhands. you can see just see it. I can understand that he has far greater trust in his forehand but these players are playing close to the baseline and they can take the ball early off either wing.
nadal gives him too much space for them to work with when he gives up the control of the center. he is just not as fast as he used to be. you cant count on those near impossible gets anymore.
he has one hell of a backhand. it is one of the best in the world. he just has to trust it more and give it chance to get in the groove in any one given match.
he also runs around his backhand as much as possible on the returns. that also gives them too many opportunities. they all have big serves these days.
nadal just has to hold his ground and trust his backhand.