Whilst I agree with you EJ, to play devil's advocate, could I not argue that it is because of Federer that those players only have one slam between them? Also you are not taking into account who he may have beaten en-route to the final - it is a bit narrow to look purely at who he has faced IN the final.
It's the Nadal H2H (in Slams, particularly) that is the biggest flaw in the Federer GOAT argument though.
Federer was clearly the best player in his time (2003-2007) but the players he was faced with in that time period were simply not good enough with the exception of Safin and Nalbandian, but specifically Safin. He came at a time when all the great players were either in decline (Hewitt due to injuries, Agassi due to old age,) or into self indulgence (Safin, Nalbandian etc.) or too young (Nadal, Nole and Andy), so Federer was basically left with a bunch of mediocre players and if Andy were to play in that time period, he too would have won most of the Slams. In any case, no one was as dedicated and motivated as Federer and as serious when it came to tennis.
Even Paul lately admitted that there's a vast difference between Sampras and Federer. Federer still gets excited about small tournaments whereas Sampras was long done with those and was very mature about everything. Sampras hated traveling whereas Federer still loves it and has given Mirka everything so that she wouldn't stand in the way of his true love. Sampras gave up tennis and retired so that he could start a family. So when a person's life revolves so much around his work, in this case, his tennis and if he's good at it, then the results are bound to reflect that as well, so we basically don't know how much others would have achieved if they were just as much dedicated and single minded as Federer. And that together with Federer's good health something he was born with as opposed to Sampras, who was born with a condition and Nadal, whose knee was always a factor ever since he turned pro. However, it is entirely to Federer's credit that he was that dedicated but in his time, the only super consistent players were Roddick and a baby Nadal and they were his main rivals.
And his en route to those finals aren't a different story as they were the same bunch playing at the same time. It's not like there are some hidden players who were great but got beaten by Federer.
Here's a list of the top seeds at Wimbledon in 2003. You can see Mark Phillippousis, the finalist, wasn't even seeded there. And you'll also notice a lot of the leftovers from the 90s.
1. Australia Lleyton Hewitt (First Round)
2. United States Andre Agassi (Fourth Round)
3. Spain Juan Carlos Ferrero (Fourth Round)
4. Switzerland Roger Federer (Champion)
5. United States Andy Roddick (Semifinals)
6. Argentina David Nalbandian (Fourth Round)
7. Argentina Guillermo Coria (First Round)
8. Netherlands Sjeng Schalken (Quarterfinals)
9. Germany Rainer Schüttler (Fourth Round)
10. United Kingdom Tim Henman (Quarterfinals)
11. Czech Republic Jiří Novák (Third Round)
12. Thailand Paradorn Srichaphan (Fourth Round)
13. France Sébastien Grosjean (Semifinals)
14. Belgium Xavier Malisse (First Round)
15. France Arnaud Clément (Second Round)
16. Russia Mikhail Youzhny (Second Round)
17. Brazil Gustavo Kuerten (Second Round)
19. Chile Fernando González (First Round)
20. Russia Yevgeny Kafelnikov (First Round)
21. Netherlands Martin Verkerk (First Round)
22. Spain Félix Mantilla (First Round)
23. Argentina Agustín Calleri (Second Round)
25. Spain Tommy Robredo (Third Round)
26. United States James Blake (Second Round)
27. Morocco Younes El Aynaoui (Third Round)
28. South Africa Wayne Ferreira (First Round)
29. Argentina Gastón Gaudio (First Round)
30. Finland Jarkko Nieminen (Third Round)
31. United States Vincent Spadea (First Round)
32. Argentina Juan Ignacio Chela (Second Round)
33. Russia Nikolay Davydenko (First Round)
34. Czech Republic Radek Štěpánek (Third Round)
So Federer had to beat M. Phillippousis, A. Roddick, S. Schalken, F. Lopez, M. Fish, S. Koubek and H T Lee to win his first Grand Slam and his first Wimbledon. And he was 22 at that time.
On the other hand, in 1990, Sampras had to beat A. Agassi, J. McEnroe, E. Lendl, T. Muster, J. Hlasek, P. Lundgren, D. Goldie to win his first Grand Slam. And he was 19 at that time.
And here's the top 16 seeds of 1990 USO:
The seeded players are listed below. Pete Sampras is the champion; others show the round in which they were eliminated.
1. Sweden Stefan Edberg (First round)
2. West Germany Boris Becker (Semifinalist)
3. Czechoslovakia Ivan Lendl (Quarterfinalist)
4. United States Andre Agassi (Finalist)
5. Ecuador Andrés Gómez (First round)
6. Austria Thomas Muster (Fourth round)
7. Spain Emilio Sánchez (Fourth round)
8. United States Brad Gilbert (Third round)
9. United States Aaron Krickstein (Quarterfinalist)
10. Soviet Union Andrei Chesnokov (Third round)
11. United States Michael Chang (Third round)
12. United States Pete Sampras (Champion)
13. United States Jay Berger (Fourth round)
14. United States Jim Courier (Second round)
15. Socialist Federal Republic of Yugoslavia Goran Ivanišević (Third round)
16. Argentina Martín Jaite (Second round)
So to sum it up, Federer time saw the weakest field in any era which basically allowed him to win 12 GSs, but from 2008 and on, it just got a lot tougher which pretty much restricted Federer to win no more than 5 Slams in 5 years span. But as I mentioned before, no one in tennis history has taken tennis as seriously as Federer and the results are bound to reflect that as well, but this, by no means, indicates that he's the GOAT given all the details.
An undisputed GOAT means someone who saw just as tough era as before and beat all his main rivals to win the most Slams and stayed on top more than 6 consecutive years breaking all the crucial records of previous times.
But ^^^ that's just for the argument's sake. In my world, the words such as "undisputed king" or "GOAT" do no exist simply because Federer's records will be broken too in the future. But more importantly, how can anyone even say someone's the GOAT when it's nearly impossible to compare the eras when there's so much to take into account such as, the surface, different competitions, the playing fields, racket technology and so many other variables day in day out. Just plain ludicrous. One is not being honest but rather ignorant if they say so.