If surfaces were Equal, we would have to split the results of AO/USO in half that way they would count as 1 hardcourt slam.
Federer (6+5 / 2 = 5.5)
Nadal (3+1 / 2 = 2)
So if there was only 1 hardcourt slam, 1 clay slam and 1 grass slam, the averages and slam total would be:
Federer 8 grass, 5.5 hardcourt, 1 clay = 14.5 slams
Nadal 11 clay, 2 hardcourt, 2 grass = 15 slams
Nadal would lead the slam total count if tennis was equal in terms of hardcourt, clay and grass.
In a more detailed twist:
If we go by their 1 best surface, Nadal would be better (minimum 11, total 11)
If we go by their 2 best surfaces, Federer would be better (minimum 5.5, total 13.5)
If we go by all 3 surfaces, Nadal would be better (minimum 2, total 15)
No matter how you look at it, Nadal is the GOAT. Too bad that Federer chickened out from playing RG because he would have had the chance to win in 2015 or 2016 when Nadal was not at his best. But Federer missed his chance to add a much needed 2nd clay slam and become the GOAT.
Another important detail is that:
Nadal was able to beat Federer on grass/Wimbledon in his 3rd try. Federer was not able to beat Nadal on clay/RG in 5 tries. That again shows how Nadal is about quality not only quantity.
Have a nice day fedtards and remember it's not too late to jump on the Nadal train and become a fan of the real GOAT. First class seats are full, but we can find you a place in the luggage compartment.