GOAT Criteria has changed over the years. Sounds like you put a strong case towards having to win all of the important tournaments at least once. However, if you take that position almost all players in history who we term great wouldn't even be in the discussion of GOAT candidicy.
Borg - no US Open or Australian open
McEnroe - no French Open
Lendl - no Wimbledon
Connors - no French Open
Rosewall - no Wimbledon
I could go on and on.
One has to remember that winning all of the majors has become easier since 2002 with the homogenization of surfaces and the massive slowdown at Wimbledon.
The season end finals has historically been a very important tournament - Nadal has never won that.
Pretty much all the great players have a hole in their resume.
The only player who probably does have any hole in his resume is Agassi (though I would argue in the 90s the Grand Slam Cup was important and he only got to the final of that tournament), and very few commentators would argue for Agassi being the absolute GOAT
So being a GOAT candidate has to be decided on a range of other criteria.....eg dominance at the top, time at number 1 in the world, numbers of important titles won....etc etc