Tony,
As I understand -- thanks mainly to some excellent research and writings by Mike Riste, of Vancouver -- Macan read Low's Concerning Golf, and other writings, while recovering from wounds (including loss of a leg) sustained during the Battle of Vimy Ridge, during World War I. Subsequently, he was a devotee of Low's architectural principles.
Regarding putting greens, Low wrote: "Whenever possible, putting greens should be of the low, narrow plateau type, with the plateau tilting away, not toward the player. No green should be higher at the back than it is at the front, for that gives a player confidence. Only half of the flagstick should be seen from where the approach shot is played."
Many years later, Macan was quote saying: "Today, the uninformed believe a green should be constructed with the slope from back to front, so that it will retain the ball. In brief, this suggests the shot should be a mechanical operation and the result a mathematical certainty. This is not the game of golf. Golf was not conceived as a mechanical operation but rather full of fun and adventure. Many things could happen to the ball after it pitched on the green. The ill-happenings were not regarded as ill-fortune or ill-luck, but part of the adventure, and the more skilled found methods to overcome the risks of ill-fortune."
Unfortunately, much of Macan's work has been erased -- including, I'm certain, a number of his fall-away greens. Reportedly, this type of green design was widely criticized by the PGA Tour pros during the 1966 Canadian Open at Macan's Shaughnessy course, in Vancouver.