Pat;
I guess I might be able to come up with plenty of examples if I thought hard about it and also did plenty of research. There are actually some good examples on some of these recent threads on this broad subject--a few good examples from Shackelford, particularly.
As for your question of the retaining of original design principles I would use the example mentioned on another thread about the restoration of a few bunkers on the fairway side of the creek in the drive area of #5 Merion.
Frankly, I really don't even know whether those little bunkers are original or not but I feel when you consider basic design principles those little bunkers are probably unnecessary--superfluous and maybe even diminishing to sublimely simple and classic design strategy.
I will cite you my feeling about how the hole would be with them and without them and you can choose what you think would be best in a design principle context.
Firstly, the lay of the land on #5 Merion is about as good and natural as it gets. You add the perfect orientation and placement of the creek on the left in the drive area combined with the very much right to left slope of the fairway towards the creek. Add to that the dramatically right to left slope of the green that filters towards the same creek on its left and you have a world class golf hole!
Now say the fairway on that hole is very wide and very firm and fast (as it should be). To get your ball down near the creek on the left is the play that is very much the correct one to hit your approach shot up into the dramatically right to left green and hold the ball on the green! You could play well away from the creek to the high right side of the fairway but then you have a much more difficult play from the right side to a green canting away from you and running your ball toward the greenside creek on the left.
So envision that drive area with a very firm sloping fairway filtering the ball toward the creek and nothing to stop the ball from filtering toward the creek. Now envision it with a few little bunkers that could only be there as a "safety catch" to prevent your ball from getting into the far more penal creek.
What seems better to you in the context of basic design priniciple? To me the creek there by itself with no little bunkers to diminish its more penal risk effect is far better. I believe without the bunkers many if not most players would tend to play their tee shots well away from the creek but then have to pay the price by being out of angle to the slope of the green. Long hitters and guys like Tiger even from the new back tee might try to bomb their drives over the cutout of the creek and past it but that is an additional option that requires and extremely long and extremely accurate drive and one that pulled off would be richly rewarded.
The bunkers next to the creek apparently show up on a 1930 aerial but I still think they are features that are unnecessary and load up one side with architecture that really isn't needed because of the brilliance of the orientation and placement of the creek alone combined with the other great but simple stuff that is naturally going on from tee to green.
I think those bunkers actually diminish simple design principles whether they were original design or not. What do you think?
But don't misunderstand--I'm all for really good restorations of some of these classic courses that are in need of it. I'm simply cautioning that in doing a restoration to a particular target date that the club doesn't remove something (or add something) that came after that target date through evolution or even redesign that may have improved the golf course.
Probably the best example and the course I know best is my own. If, for instance, we decided to restore back to 1930 at Gulph Mills (1919 Ross) we would remove some excellent holes that Perry Maxwell redesigned later in the 1930s.
If a golf course was not aware of that fact or for some reason didn't appreciate the Maxwell holes they might take them out and go back to what they were originally with Ross's design.
It is important to be realistic with some of these classic designers and realize what didn't work and why and really look at the reasons they might have changed. We did the research on that very thoroughly and came to the same conclusion that the members did back in the 1930s. That was that a few of the Ross holes just weren't good and they were not working well for anyone. Maxwell fixed those problems and through the years the holes that were originally weak or not working well and were later redesigned by Maxwell have become some of the most respected on the course!
Some people seem to suggest that because it was Ross that nothing could possibly have been wrong! They tend to unnecessarily deify him to such an extent that he could do no wrong. That is not intelligent architectural analysis, in my opinion.
Others might say something like everything should go back to original Ross (despite Maxwell's good hole redesigns) just to keep the course "in character". I personally don't like that attitude either and think that a blanket attitude like that is very dangerous!
Another interesting example is another course I know extremely well--Gulf Stream G.C. in Delray Beach, Fla. #15 is a wonderful little delayed dogleg or delayed mini cape-hole that was one of Ross's favorite holes--so much so it was mentioned in his book. Quite a few members are aware of this and I have been also for many years. What I didn't know until this year is that Dick Wilson reoriented and redesigned the green on that hole! I was shocked to learn that fact since the hole with its present green is basically simple brilliance. So I looked up the original green drawing by Ross and sure enough the green and its entire orientation was much different and didn't appear anywhere near as interesting or strategic as it is now.
So those are a few good examples of courses and holes that I think would be diminished or hurt by restorations to something that existed before them.