Laver himself in his new book calls the 4 Major Events he won in 1967 simply the 4 most important events of the 19, he won overall, and calls it "a good year". It was always the quadruple thing, which reminded me on a real Grand Slam. Maybe his level was higher, but i still rank the 1969 GS higher, because he had also to face (alongside the usual suspects of his contemporaries) the younger, hungrier generation of Newcombe, Ashe, Roche, Okker and Smith, who threw virtually the whole kitchen on him, as we can see in some matches recorded on video.
On the great amateur years a i would add Sedgman in 1952, Trabert in 1955 and Emerson in 1964.