Matthew,
Having had loads of experience on lesser courses, before ever being exposed to some of the greats, I can honestly recall how the use of diagonal bunkering, caused me to have to think, for the first time, on the golf course about strategy.
Introducing strategy to a newer golfer is in my narrow view, the diagonal's highest function.
It wasn't until I played Cypress Point did I understand they were all stolen concepts.
However, the use of natural diagonals, ala the 8th at Pebble Beach, likely preceded Mac's use of a string of bunkers, ala #2 and #5 (?) at CPC.
The original 11th hole at Pinon Hills, from the back tees, is one of the best uses of a natural diagonal during the dark ages of gca (mid-late 80's). Even Desmond's use at that So Cal course quail ridge? ( I can never remember that name) is a top notch use of terrain.