I'm a hardcore Nadal fan, and I'm saying it's a joke to call him co-GOAT. By saying that, you're placing him on equal footing as Federer from a historical perspective, which objectively, he simply isn't. It's one thing to say he's the same caliber, or use them as a tier of their own, which is fair, but to call Nadal co-GOAT is based on nothing concrete. He's factually less accomplished than Federer, is he not?
And by the same token, why not put Djokovic on the same footing as Nadal? Hell, the gap between Nadal and Djokovic in majors is the same as that between Federer and Nadal, and outside of majors, they are much closer in accomplishments than Nadal is to Federer. So why aren't we lumping the two together?
Historically, Federer > Nadal > Djokovic. It's pretty simple.
Good post, but let me somewhat veer into Devil's Advocate territory. By "historically" you seemingly emphasize accumulative accomplishments - I have no problem with that and, in the end, it is the only way we can really judge and compare players in terms of historical rankings, because the record is actually what happened without interpretation.
That said, that's the big picture, or "macro-level." From the "micro-level," or the ground floor so to speak, the three mentioned are much closer in terms of greatness. Sure, it plays out as you say in terms of accumulated records and therefore all-time rankings, but if we look at "greatness" as more of a qualitative thing, they are much closer. In fact, I would even call them "co-GOATs" in that measure alone - and yes, all three of them.
I am reminded of Ken Rosewall and Lew Hoad. Rosewall's record is clearly far superior, especially when you take into account Pro Slams, but for a few years in the late 50s, Hoad was up there with Rosewall, Gonzales, and Laver as the best of the best, and some even said that he was the greatest of the bunch
when he was playing his best and healthy. But in the end, Rosewall was the greater player - because greatness isn't only about how good you are in a given match, or even over a short period of time. It is the sum total of one's accomplishments.
But here's a question. In your mind, what would Rafa have to do to surpass Roger in terms of historical greatness? Would one more Slam than Roger be enough? What if all five (or more) of those needed Slams were RG only? Or would he need to narrow the gap of weeks at #1? Win at least one WTF? Etc. I'm guessing it isn't one thing in particular, just wondering what his resume would have to look like--relative to Roger's--for you to give him the historical edge.