I think it is worth discussing. Nadal has made it to both HC Grand Slam finals since he's comeback and would surely have won both if not for the back injury. On Clay in 2013 and 2014 his success comes more from lack of depth in the field of good clay courters than it does from his good play. He played very lackluster throughout the whole of the 2013 clay season (barring a few good moments and matches here and there) and won a lot of his titles because of lapdogs in later rounds of tournaments (Almagro, Wawrinka, Federer, Ferrer) and even some hardcore choking (Ferrer Madrid). It's not that Nadal was spectacular, it more that the competition lacked. Whereas on mid to high bouncing hard court since his comeback, Nadal has only lost to Djokovic in Miami and Dolgo in Indian Wells. I believe at this point in his career, the past is the past for Nadal on clay and he will do better on Us Open style hardcourts now. That doesn't mean Nadal still won't dominate the clay season but he's going to have to play well or hope that no one shows up ala 2013, or a combo of both.