Since the 2019 Grand Slam season just ended, I want to bump this thread. In my opinion, the race between Djokovic and Nadal is probably the most interesting slam count "race" between the Big Three.
In recap, here are the stats at the start of 2019:
Nadal: 17 titles
Djokovic: 14 titles
Here are the stats at the end of 2019:
Nadal: 19 titles
Djokovic: 16 titles
As you could see, the difference did not change (with Nadal still having +3 advantage over Djokovic).
Here's my two cents on the "race" between these two players:
I think Djokovic will have more chances to win more slams because he is 1 year younger BUT I think Nadal will win enough slams to keep his lead over Djokovic.
Like I said before: Djokovic does not have an "advantage" over Nadal like Nadal has "advantage" over Federer in terms of the rate of winning slams. Here's what I mean:
In order for Djokovic to surpass Nadal, Djokovic has to win at the very least 4 more slams. But here's the problem: Nadal has an equal opportunity of winning a slam just like Djokovic. Here's a rate:
Djokovic - 4, Nadal - 0
Djokovic - 5, Nadal - 1
Djokovic - 6, Nadal - 2
So basically Djokovic has to win those slams just to surpass Nadal in the slam count. Unfortunately for him, if Nadal sneaks in 1 or 2 more slams then it will be really hard for Djokovic to surpass Nadal.
Before everyone says, "Well Djokovic just won 4 out of 5 slams before the US Open and he is the number 1 player in the world..." Just like Nadal struggled with nerves and being passive, Djokovic also struggled with nerves and being passive in the Wimbledon final in July against Federer. In addition, he just had a shoulder injury so he is not automatic anymore when it comes to winning slams. He is still the favorite in Australia and Wimbledon but he is not clear cut favorite in those two slams. Finally, if Medvedev continues the level play he has shown during the summer then it will be interesting on how Djokovic and Nadal move forward in the slams.