Paul-
That's the whole crux of the problem. Yes, an architect could leave weak points within a course.
I still prefer both avenues of thought; a fixed point in time and/or what is in the final plans. Now that I work backwards on GCA, it was Aronimink that took this route (using Ross' plans as-drawn)
Both approaches have merit.
I know of some clubs that went forward with the idea of modernizing/renovating their course, without using the 'fixed point in time' benchmark or as-drawn plans. That is fine for them, it's their course, and I'm not a member, thus I have no say.
I have many reservations about the statement "if you recognize a flaw on a great course you should fix it", just for the reason that it's very open-ended and subject to interpretation. I like the spirit of the statement, and in the right hands it can be a wonderful thing, but overall, I feel that in the dynamic of a green committee or membership where members are changing, this can be a very dangerous thing, and I am only speaking from what I have observed on here, because again, once the door is opened, it can be hard to close.
I'm hesitant to try to define 'right hands for the job', because again, this leaves the door open as well, which is why I again go back to either a fixed point in time or as-drawn plans.
One of the things I have learned on here from one of the 'senior' members of this board is that there can be little regard for the past. I'm still thinking about this in conext of this question/post and will elaborate later, but wanted to throw it out for the group as a whole.