I think this is now an interesting question at this stage. Federer has 9 hard court majors, and Djokovic now has 5. However Federer will be hard pressed to win another (he "could" win 1 more, but it is far from certain, he might never win another slam, and he is more likely to win Wimbledon than another U.S Open at this stage), while Djokovic is virtually certain to win atleast 3 more hard court majors. Will he win 4, 5, or even 6 (or more) more? That is a bigger question and is hard to tell. I think it could be very close in the end to who wins more hard court majors. So who at this moment would be predict wins more hard court majors. I could see something like this: Djokovic- 7 Australian Opens, 3 U.S Open if that is what Djokovic wins, then Federer would need 1 more to end in a tie.