I see no reason not to "buy it." Movies are, in fact, rated based on subtle criteria and individual judgment. The difference could simply have been that different people are sitting on the MPAA panel today than were there in 1979.
It's certainly possible. Having read quite a bit about the MPAA in the past few years, the ratings board certainly doles out ratings based upon individual judgment. Any "subtle criteria" they may be applying seems to be rather undefined and ever-changing--I think you're giving them too much credit there. But I also have to acknowledge that I view the ratings board very cynically.
I'll grant that there were probably other factors at play here, but there's no need to see it as cynically as you suggest. As has already been established in this discussion, back in 1979 it was far more common for science fiction in general -- and Star Trek in particular -- to be perceived as children's programming. As someone remarked earlier, ST reruns often aired in daytime slots, and there had been an animated ST series just five years earlier, so the show had a sizeable young audience. At the time, it made sense to think this was a film that should be appropriate for general audiences. But the Director's Edition came out in a time when ST was more regarded as programming for older viewers, and of course it was probably aimed at established fans and collectors as much as anyone else. So it stands to reason that the way Star Trek would be perceived by the people responsible for determining its rating would be different.
Again, it's possible. I just think you are underestimating Paramount's position, concerning both the stigma that has become attached to the "G" rating since the late 70s as being exclusive to children's entertainment and with the studio's desire to suggest that the changes made to The Director's Edition were dramatic (which a new rating rather slickly suggests).
And where in the hell did you get this notion that the MPAA bows to the studios? If anything, it's the other way around. Studios and filmmakers constantly have to tweak their films in order to get the MPAA to give them the rating they hope for.
The MPAA has always been the lap-dog of the major studios--or at least, given them preferential treatment. The creation of the "PG-13" rating in 1984, for example, was directly to the benefit of the studios. It is independent producers who run into the most trouble with the ratings system.
Kirby Dick's documentary,
This Film is Not Yet Rated, goes into detail on the subject. Matt Stone and Trey Parker explain in the documentary how they had no trouble getting an R-Rating for
South Park: Bigger, Longer, and Uncut (produced for Paramount), but found it impossible to secure the same rating for
Orgazmo (produced independently). They were forced to release the latter with an "NC-17" rating, effectively crushing any potential business it might have had.
Not at all. The DE of TMP was treated as a new product when it got rated, and it turned out "PG". I'm fairly sure that the more recent DVD release of TMP's theatrical version was back to being a "G".
I understand why it went to the MPAA for re-rating. However, I disupute that the changes made to the Director's Edition had any discernible effect as to how "intense" any sequence in the film happened to be. Either the rating changed because the MPAA's standards have changed, or the rating changed because the studio wanted it to, or both.
The theatrical version remains rated "G," however. I'm not sure what the protocols are for re-submitting an unchanged film to the MPAA for a
harsher rating.