In my experience,
The biggest differences I can think of are:
Greens - The ODGs weren't afraid to build wild greens compared to today. This could be mostly due to current mowing heights, but still you see very tame greens on almost all new courses. Who would have huevos to build something like #16 at Pasa these days?
Very thought provoking. Off the top of my head I'm not sure your generalization holds true for Ross and Flynn, among others. Certainly Mackenzie's work was bold as was the work of Macdonald and his progeny. My sense is there were two schools then and two schools now with respect to the wild greens options. Interested in what others think.
Mike
The greens at Old Macdonald are certainly as wild as anything Mackenzie ever built - outside of Sitwell Park!
So there's another theory shot to hell....
Ok Fine,
We'll make one exception. So we're down to 99.999% of courses don't have wild greens!!
All joking aside, sure there will always be a few exceptions to the rule, but the theory is still good in that the vast vast majority of new courses built today have at best boring to so-so greens as a collective group.