I can't believe I actually made it through the gauntlet. I didn't read everything, but skimmed it all. An entertaining, if headache-inducing, read.
The irony is that about a week ago I wrote a blog post about Rafa's chances of being the GOAT but didn't polish it up. This thread kind of makes it superfluous, but maybe I'll revisit it and post it in a few days.
A few comments to make. First of all, and perhaps most importantly, when we talk about the "GOAT" at the end of the day we're not talking about how good a player was at their best, or how good they were versus specific players, or any combination of specific stats - we're talking about overall career greatness. The whole shebang. There are numerous factors but the most important two are, in my opinion, Slam wins and weeks at #1.
My view is that Rafa has to equal Roger's Slam count to be considered the greatest ever. He won't catch him in weeks at #1, although his superior Masters record equalizes Roger's World Tour Finals. Other factors all seem to even out. we could even say that Rafa's H2H superiority is cancelled by Roger's weeks at #1, so we're left with Slam count.
I think the tie goes to Rafa because of the H2H, but that Rafa needs to tie Roger to be considered greater. If he gets to 15 or 16 it will be close, and we'll debate it for years to come, but 17 and its Rafa's, 14 and its Roger's; 15-16 is up for debate.
One note on H2H. While I think it does mean something, some are putting way too much emphasis on it. As others have pointed out, some match-ups are just bad. Did you know that Becker was 25-10 against Edberg? They're considered just about equal historically. Vilas was 6-5 against McEnroe, but Johnny was a much greater player. Etc. Two factors must be kept in mind: the way two styles of play match up against each other, and the age at which those players played.
Its interesting to note that Roger's very best year, 2006, in which he had an amazing 92-5 record, but went 2-4 vs. Nadal (he was 90-1 vs. everyone else!). Yet in 2007, when Roger was starting to slip a bit - his 88% being his lowest since 2003 - he had his only winning season vs. Nadal, going 3-2. The fact that this doesn't prove anything actually proves something: H2H matchups don't mean much of anything relatively to the overall field. Federer dropped a small step in 2007, then a larger one in 2008 and never really gained it back except for a great half year in 2012. But their H2H wasn't really any different than it ever was, at least until 2013. From 2009-2012 Rafa was 6-4 against Roger, despite the fact that Rafa was in his prime and Roger in decline.
One final remark. While I realize that Open Era tennis is distinct from what came before, I think we should clarify that when we are talking about "all time" or "Slam record" we're really just talking about the last 45 years. When talking about professional tennis history going back almost 100 years, Roger Federer may not even be the GOAT.
Let us not forget that the actual Slam record - including Pro and Amateur Slams - is Ken Rosewall with 23. Rod Laver is second with 19, and then Federer and Pancho Gonzales are next with 17 each. We might look down about Pro Slams, but note that the best players in the game were playing them and there were only three a year, so the competition was comparable. Gonzales was the greatest player of the 50s, Laver of the 60s, and Rosewall probably the second greatest player of both decades. These three men, in my mind, are three of the greatest players of all time and each has a good case to be considered the GOAT.
In the end, I'm left with five candidates: Gonzales, Rosewall, Laver, Federer, and Nadal. Bill Tilden, Bjorn Borg, and Pete Sampras all fall just a bit short, for various reasons. Nadal's record might be a bit shy of Sampras', but he's fast closing and I think in another year or two he'll have the greater career. After those seven there's a big drop-off to the next tier of greats, none of whom have strong arguments to be GOAT candidates (Budge, Kramer, Lendl, Connors, Agassi, McEnroe, etc).
So if Rafa is going to be considered the GOAT, he needs to pass not just Federer, but also Gonzales, Rosewall, and Laver - not to mention Sampras and Tilden.