Tom, you asked, "What about changes to his architecture...like what was done at Bethpage-Black? Or other important courses of his that have been changed, like Brook Hollow, Baltusrol-L and Shawnee-on-the-Delaware."
I try to view his courses in the amse vein that tilly did. He believed that his courses should adapt to changes in technology. He himself made changes to some of his own courses, so course changes in and of itself is not necessarily a bad thing, or in this case, crime against the architect. In fact, after visiting one of his designs during the PGA Tour, Tilly wrote that it was time for him to "take his own medicine" and so he recommended some changes.
For example, how can one argue that the present 16th hole at Augusta be replaced with the old hole with green in front of the creek and removal of the pond? It is by far and away one of the two most most memorable par-threes (IMHO) in major championship golf, the other being a few holes earlier on #12. For every person who will tell you I remember Watson at 17 at Pebble as the shot they most think of at a par-three in a major, I believe manymore will talk of Nicklaus nearly making an ace in "86 or Tiger and the NIKE commercial his shot created.
Candidly, a better hole is a better hole and any architect would accept that.
Now you and I differ as to what constitutes a "change" to a course. For example, in my opinion, the simple act of moving a fairway bunker is not in and of itself changing a hole if the purpose of the move is to restore and bring back the original design intent of shot angle.
An example. The bunker that guards the left corner in the fairway of the 4th hole at Bethpage Black. Tilly designed this hole to take advantage of several natural features of the terrain in a very imaginative way. First, there is the change in elevations by playing to two distinctly different plateaus. What makes this the work of art was how he used the downslop from the first plateau to entice the accomplished player to try and bite off more than they might chew so to speak. He did this by placing that fairway bunker at the outer limits of a long carry.
The result was that 3 choices faced the player on the tee. First, do I play safe and drive straight and leave a very long second shot to the upper plateau, guaranteeing a short third that will have to come into a green that slopes directly away and bring the front bunker into play. Second, do I attempt a long draw that will allow the ball to turn around the corner and allow for a second shot that can be placed up right of the green where an open and easy pitch can be played. Third, it enables the player to ask the question, how strong do I feel today? It gives him the option of attempting to carry the bunker altogether, and land hard so that the ball kicks off the gathering downslope and is propeled far down the fairway. From that point a new set of shots become available, including the ability for the heroic play in an attempt to reach the hole in two with a perfectly played fairway wood/long iron. Of course, a poorly played drive, especially where the latter two options were being attempted, would result in potential severe penalties of either rough or sand.
All of these options because of a carefully placed bunker.
In the renovation/restoration (it was both) to the course, this bunker was moved forward and slightly right. As a result, what was a 230 yard carry from the lower tee became a 270 yard carry from the new upper one (this tee was made in the 80's by Chuck Workman).
As a result, the choices for the accomplished player dictated by the original design intent of Tilly were RESTORED. As the course was designed to PRIMARILY challenge the best players, the moving of this bunker is NOT a change, but a restoration, and a very good one as it also doesn't impact the play of a lesser player who would never face these decisions anyway.
On another thread, when I mentioned the idea that bunker movement for the sake of shot angle restoration is not a change but could be considered a restoring, Tom Doak stated that he disagreed with the concept of bunker movement as rarely had he seen this done well and usually poorly. This hole may be an exception to that statement or not, I am of the opinion though that it can be done properly and well if the intent of restoring the angle of play is the primary goal.
So to answer your question, I believe one has to take a hard look at individual courses and at times, even holes, to decide whether work done was first a change or restoration and secondly whether or not it was done well.
Finally, and I am not wanting to debate this with you as i respect your right of opinion, but the only true change done to the Black was at the green complex on #18. Frankly, since it was universally accepted that something needed to be done to the hole to bring about as proper a finish to the Open as possible, a change needed to be made. I know that I am in the minority in this, but I think it held up well, being ranked as the 7th most difficult hole for the championship.
Courses such as Baltusrol & Shawnee have been greatly changed over the years, but the same has happened to many a great course. Maybe this leads to my 4th "crime then, and that is the lack of appreciation that players, especially from the 60's onward if not before, have had for the history of the game and the design concepts of the course he is playing or club he belongs to.
It is this attitude that leads to the ego of green committees making changes such as at Tilly's Dellwood where because complaints were made that the greenside bunkers were just too difficult that ALL of them were dug up and moved further away from the greens and made smaller and easier. Today the club is trying to slowly restore what they had destroyed.
So to boil that crime down to as short a phrase as I can, uninformed changes made because of ego and/or lack of understanding of golf course architecture.