Jonathan:
Actually, when I used to run the GOLF Magazine rankings years ago, I was pretty surprised at how many courses some of the architects had seen or played.
After the guys like Bob McCoy, and Masa Nishijima, the ones who had seen the most were Tom Ramsey (the Aussie golf writer) and several architects -- RTJ Sr., Pete Dye, Michael Wolveridge, and Dana Fry are the ones who come to mind. It IS our business to understand golf courses, after all.
I think Sir Bob Charles was very high on the list of courses played, too, since he had played all three tours for many years. Some of the other pros' lists were not as impressive as you might have thought, though.