Attacking Nadal's backhand wing by using different angles and depth, and continue doing this until Nadal's backhand crack down to give them free point, it has become one of tactics for beating Nadal. I believe it makes Nadal confuse on what he should move due to pressure while his opponent using this tactic well. This tactic is one of the reason why he lost to Djokovic.
And we have said it a lot of times. So to think based on this point, how to avoid same circumstance is the key for Nadal.
But so far this year, personally I haven't seen a lot of change on Nadal game. He tries to use backhand slice, but it is too predictable. He needs cross-court backhand slice to help him. But, I never saw it. In other hand, I believe he needs to run round his backhand, to hit his massive forehand cross-court if he has chance. But major opponent already know that so that is reason they continue play the ball with different pace, angle and depth.