Some of us think there can be no GOAT, esp. because of any notion that there can only be one. But to call Nadal "limited" is ridiculous. Because of such a great clay resume? Seriously, the man is one of the few men with the career slam, esp. since the Majors have been played on 3 surfaces. On Hards, he has 9 Masters 1000, 1 Olympic gold, and 5 Majors. Novak on clay: 9 MS, 2 Majors. That's more limited, by the surface.
This idea that Rafa is somehow not great off clay is silly, and not borne out by facts. I think part of it is due to his "uber greatness" on clay, and the subconscious contrast people make between his clay and non-clay performance. As I've said before, on clay, Rafa is the most dominant player in tennis history; off clay, he's still an ATG, just more in the pack with a bunch of others. Or to use GOAT points:
CLAY
1. Rafa 401, 2. Borg 166, 3. Vilas 165, 4. Djokovic 162, 5. Lendl 138 (Roger is #6 with 113)
GRASS
1. Federer 185, 2. Connors 130, 3t. Sampras 101, Djokovic 101, 5. Newcombe 97 (Rafa is #16 with 48)
HARD
1. Federer 471, 2. Djokovic 470, 3. Agassi 253, 4. Nadal 233, 5. Sampras 229
CARPET
1. McEnroe 212, 2. Lendl 185, 3. Becker 172, 4. Connors 163, 5. Laver 109
As you can see, Rafa's lead on clay is 2.5 times over #2. Or to put it another way, he's compiled a clay record better than any two other players, and as good as #2, 3, and #13 combined. That is insane.
Roger is the best on grass, but doesn't have nearly the gap. He and Novak are virtually tied on hards, although clearly Novak will pass him shortly - pretty much his next tournament. And Mac has only a small edge over Lendl on carpet.
Now GOAT points are limited and over-emphasize longevity - thus Vilas ranking #3 on clay, having played 841 clay matches, which is 122 more matches than anyone else, and almost three times as many as Federer (297). And obviously Borg was far greater - he as basically the same number of clay GP as Vilas, but in less than half the matches (329. I'd rank Borg, Novak, Lendl, and Wilander over Vilas as a clay player, probably Roger too, though Vilas was very good clay - sort of the Thomas Muster of the 70s.
I'd probably rank Rafa higher than the 16th best grass player, especially over some of the guys who played back in the day that simply played more on grass, like Roche and Smith. Maybe he belongs more in the #10-15 range or better, which is still very good.
One final GP note. If you take out Rafa's clay GP he's at 281, which would still be good for #14 - just ahead of Wilander, Vilas, and Nastase, but behind Becker and Edberg. Meaning, if Rafa had never played a clay tournament and instead swapped them for a combination of mostly hard but some grass and carpet, he's still probably be as good or better than Becker, Edberg, and similar to Agassi. In fact, you could say that Rafa is Andre Agassi on hards, Andy Murray on grass, and a better version of Borg on clay. Or if you take only his clay GP (401), he'd rank #10 in the Open Era, just behind Agassi. That alone is rather extraordinary.
Maybe I'll crunch some numbers and look at GP per match played by surface. That might be interesting to get a better sense of peak level on each surface.