Re: Will Nole surpass Nadal's GS count at the end of their career?
At the moment Djokovic seems like the favorite for the AO and USO when he is fit, and have a chance to win one of the other two. Personally I expect him two win around 2 slams on average a year with this form. About 6-9 more to pass Nadal? So that is roughly 4 years at his current form and the form of the current competition.
But fitness and also confidence can drop anytime, Djokovic relies heavily on both. His serve and forehand(two most important shots in tennis) are decent for top10 level but he can't really make the difference with these shots. Other top10 members will come in the next 4 years with a better serve and/or a better fh than Djokovic and Djokovic must be faster than them also when he is 29 if he is to pass Nadal in my opinion.
Federer (and Nadal on clay) had in their prime super movement but also the best shots, so at that time they looked more dominant than Djokovic now. I think they were able to win a couple of slams when they were not at their peak fitness due to their better shots when their movement was all of a sudden not that superior . So for them it was fitnesswise easier to be in contention for slams so many years.
I don't expect Djokovic to get more slams when he leaves the top3. And keeping his fitness at this level for another 4 years will be hard. He has been sliding the hardcourts at top level since 2007... But on the other hand when I saw him doing that in 2007 I thought he would go the hewitt road with his fitness. The guy must have the perfect body to move around a tennis court.