I think its a regional thing as well. I personally don't like it, for the clutter and complexity reasons stated. I really dislike cars with disconnected A/C systems but half of the crap still hanging around. If its there, it needs to be ALL there and working. If its not going to be used, I don't want to see any evidence that it was ever there. I don't pay more for working A/C, but I don't deduct for it either. Partial systems, however, I would deduct for either the cost of fixing it or properly eliminating it.
That said, I've talked to many customers in South Carolina/Florida/Texas who won't consider a car without A/C. Lack of A/C or availability of a good aftermarket setup is a deal breaker for them, and they add value for working A/C, or even a mostly complete A/C setup.
As for "real" musclecars having to be bare bones, I would say the Stage 1 Buicks in particular shoot holes in that "rule". I all for anything that scares you when you nail the throttle. I'm getting tired of cars that scare me when I hit the manual drum brakes.
