I think anybody who says that conditioning is not important is being disingenuous. I would argue that the greater the course the more important the conditioning, due to the fact that the features which define "greatness" (e.g. green contours, hazard nature and placement, strategic options offered, etc.) only really shine when the course is maintained optimally. I think it was Tom Paul who first compared a properly maintained golf course to a finely tuned engine, and he was right. Playing a great course in medicore condition is like driving a Ferrari that sorely needs it's 15,000 mile service check. It's still a Ferrari, but you know that you are missing something that could be truly memorable.
Of the "great" courses I've played, 5-10 were not anywhere near their best when I first played them. Of the half of those I've been fortunate enough to later play when they were finely tuned and ready to roar, the difference between the two states is almost incalculable relative to the quality of the experience. Yes, it is possible for anybody with a modicum of love for architecture and experience to hypothesize how a course "should" play when seeing it under sub-optimum conditions, but any such hypothesis is as valid as those apocryphal Platonic phoilosphers who interpret the world outside of their cave by analyzing the shadows of that world cast by the light of their internal fire. In my opinion, of course.
Given that most of us play most of the great courses we are lucky enough to get access to very infrequently, maybe even only once, such golfus interruptus is a sad but inevitable part of our life. However, just as bad sex is better than no sex, playing an architectural gem even when it is soft and soggy rather than fast and firm is better than not having played it at all.