I think this whole idea of copying holes is basically misunderstood. And of course actually attempting to duplicate or replicate any particular hole is even more questionable.
I really don't think if you had asked MacDonald what he was doing at NGLA and some of the other follow-up courses done by him and particularly Raynor he would say he was actually copying anything except very interesting and valid architectural concepts and probably at most only in a similar arrangement.
I think there's a huge difference between an actual attempt to copy a hole and creating architecture that could be considered a "conceptual copy" or the use of a similar theme or concept. The latter makes much more sense and requires interpretation and talent too.
A "concept copy" to me is basically offering the golfer similar strategic problems, solutions and demands. In modern lingo very similar "shot values". If the concept copy looks mostly the same, similar, not similar at all or even unrecognizable from its inspiration, it really matters not. What matters is how it works, functions, what it makes the player think and do and what the ball does.
There's certainly nothing wrong whatsoever in comparing concept copies, the so-called "copies" with so-called "originals" or that which may be a particular hole's inspiration. I think it's quite wrong though and misleading too to critique a hole that was inspired from another as to how exact it looks to the original or inspiration--certainly including the look of what surrounds it. The question and interest should be how well does it work and play compared to the original or something from which the basic concept came.
NGLA's Redan, Road Hole and Eden work extremely well in their own setting. So do many of the others around the country to varying degrees. Piping Rock's Redan works extremely well but with some clear differences to NGLA or probably North Berwick (which I've never seen). The fact that it's higher and a bit blinder is an asset of Piping's, I feel.
Same with the Road Holes, although I've never thought that Piping's quite stood up to the others and I grew up at Piping. NGLA's Road hole is a similar green that has a similar look in shape, orientation and probably playability but the rest of the hole is different than #17 TOC and was clearly intended to be probably because of it's own unique setting.
The Road holes are likely a perfect example of what MacDonald was actually doing with his borrowing of basic concepts from Europe. This particular hole and some of the others (Road Holes) like Piping's is probably proof positive of the misunderstanding. If I'm not mistaken the Road hole is the only one of the so-called famous MacDonald "copied" holes that is not a par 3!
Piping's was actually designed as a short par 4 so it can be seen that MacDonald was creating a slightly different arrangment off a basic theme and intended to do so! As to the actual road he simply rearranged with another feature. If MacDonald thought an OB was an absolute architectural must he could have put one in, since it's not mandatory that OB be off the course's property--I know that for a fact and even my course has "false" OBs, although they are near the property lines!
Since the other famous "copied" holes are par 3s obviously the tees and the green need to be set up somewhat similarly to function correctly. But still the architects clearly rearranged slightly off a basic theme for valid reasons. The reverse redans were simply another good example of rearrangement off a basic theme or concept. If there's an original reverse redan somewhere at North Berwick or somewhere else in Europe that preceded some of MacDonald/Raynor's, I've never heard of it.
NGLA's Eden is a marvelous hole to play--very dicey for a par 3. There's actually a ton of low margin for error aspects on it, in the approach and most particularly the front of the green! The overall slope of the green is extremely well done and significant. It may not have the same backdrop as the original or Fishers but I never felt inclined to play the backdrop and frankly never have.
Why did Raynor continue on with such close "concept copies" of so many of NGLA's famous "copied" holes? I don't know why but if I were to guess I would say because that's the way he learned the design business off of NGLA (their first course together). And Raynor was an engineer by training. Obviously MacDonald taught him well the interest and utility of clearly working off of valid, well known themes or concepts even if they were completely recognizable or recognizable pieces and parts of some original holes somewhere! Plus NGLA was a very famous course because of it's early uniqueness and they may have just decided to stamp out some relatively close variations on a theme. It's certainly possible too that when Raynor was on his own he possessed the technicial know-how but possibly not the wide "conceptual" knowledge or talent of C.B. MacDonald.
MacDonald was clearly scouring Europe for interesting architectural concepts and the fact that a few of his best known ones were par 3s probably helped create most of the fallacy that he wanted to actaully copy or duplicate original holes. He wanted to find concepts that he could use for various arrangements and even said so (I'll try to find his quote to that basic effect).
Really valid and intersting concepts and playabilities are probably a bit less numerous than we think they are and the variations or even slight variations are really the interest. The deal is in the differences, even if they're nuancy.
Features, concepts, variations on strategies, even slight ones, surrounds, looks, they're all just the "notes" and it's in the arrangements, not in the duplication. At least that's always been my understanding even from the words of MacDonald.