As we all know, the road hole bunker had been remodeled, reshaped and raised and lowered several times. Even Old Tom tinkered with position of bunkers, shapes, and reconstruction.
But, as Jeff says, re-contouring the greens is beyond what has ever been done in history (at least as I understand it).
There has to be a line that should not be crossed. But, I am not certain who or how that line can be defined and enforced. Or, is it a moving line? Tradition seems to be a large consideration. We can't actually go to intent, since TOC evolved and is not one designer's intent. We need to examine the quotes and literature of the legendary Old Course golfers, about how they played a certain hole in competition, even ask the caddies who have both been there many years, and who can relate stories handed down to them by older caddies, regarding how various holes were played, to evaluate if a tweaking is in order.
But, it has always been referred to as a natural golf course that is subject to the elements of winds, temps, precipitation, that have random effects on scoring from easy to brutal, moreso than most all other courses, and how that is the tradition of golf that should dictate that this one course, TOC, should not be subject to whimsical tweaking.
It is said how so many of the golden era architects were students and products of their experiences at TOC. From MacKenzie to Ross, to visitors like Tillie, and even Des Muirhead had developed a reverence and body of memories that informed their sense of the game, its fields, and how it was meant to be played.