Re: your point 4, we can refer to 2017, when Federer was the best player of the year, but Nadal was the No 1.Some reflections in rapid sequence.
1) there are not only those that "strangely" are called Pro majors also because in many cases are editions popped,
2) many events are to be considered big
3) the goal of this thread is to understand who was the number one a year, we went in that direction and in rare cases we did not agree with Ivan and Dan
4) in a few cases the best player is not the number one, IMHO
5) the tour included too few tournaments in the Kramer Era
6) Kramer was too strong but always had in the WS the third top player not the second although almost certainly would have won the WS
7) I have discovered some editions of big tournaments really valuable: in Los Angeles, Cannes, Geneva, Milan, and in various australian locations
8) Riggs was certainly ATG although heavily penalized by the WWII (as Budge)
9) Pancho Era tours are more structured
10) I always thought that Pancho was GOAT contender as dominant but I didn't think was so dominant
11) Rosewall is already very competitive at the end of 50s and almost always wins, you understand why it is a great player, ideal for a tournament format
12) the organizers of the Pro Tour seems not to sympathize with Segura that seems more successful than Sedgman and me impresses a lot
13) Hoad is the only top player playing at a level near Gonzalez
Also possibly Djokovic/Murray in 2016, Lendl/Becker in 1989. I’m sure there are other examples in older eras.