They are young and they still dont have strenght to play against top players. But mostly because this generation isnt that talented. Djokovic isbenefiting slower courts but he doesnt mind faster eather, Nadal obviously loves slow courts, Murray same as Nole, and Federrer benefits most. Maybe he wouldnt benefit if he was in 2004-2007 but now with his age i think this courts are helping him, he can defend well against ballbashers most of the time and run down a lot of balls. If couurts where any faster i think Clownga would blow him out of court 2 days ago.