I dislike Nadal, and I like Djokovic, but I wouldn't see a case for Djokovic being above Nadal until he gets to at least 12 Slams. I don't attach any value to ranking-related achievements.
I think he means that novak is really closing in on nadal in several regards. He's already surpassed him at weeks number one, and the difference in WTF wins is glaring. Take away novak's dominance at AO, and take away Nadal's dominance at RG... Novak has 5 Nadal has 5.
I agree with the general idea that Nadal's dominance on clay has kind of "over buffed" him because it really inflates his GS count. And his h2h with roger combined made him seem like the greatest. He'll forever be the GOAT on clay, but you take that away and on the rest of the surfaces he's lost quite a lot to people not of major winning caliber. To me that's a huge knock on his "Tennis GOAT" status, whether it be for roger or novak or anyone else.
I don't however think that slams can be replaced by masters 1000's events. Masters and slams together make the ATP points race, and that is simply summed up with weeks at number one. So yeah in that category novak has surpassed nadal. He really played very well this entire year. I didn't think he'd do as well as he did. I'm impressed with another 3 major year, and he was remarkably close to a calendar slam next to a career slam. Yeah he lost in a pretty brutal way at the french, but technically being two sets away from a calender slam is frankly an incredible performance for the year.
I think it's silly to start talking about novak's goat status just yet. But he's definitely making a strong bid for the best hardcourt player of the open era in my book. Assuming he can win another 2 hardcourt titles, he'll equal fed in HC majors.