So they cleaned up the one that was the hardest to restore and then took all the other 5 movies and just rescanned existing prints at 1080p. Then they did a quick clean-up on those with standard 2K scans.
So we got one out of six true restorations and five that are just scanned at 1080p with a later digital clean-up.
Really? From what I've read the other five films were merely taken from existing video masters made back in the early 2000s for TV broadcasts, rather than actually bothering to rescan them for the blu-ray release. That explains why there was DNR applied to hide the imperfections of the scans.
However, it's actually not a bad method had they handled it much better. This is typically done for many films out there, but for whatever reason the Trek films came off the worst.
Here's a good example of a film being cleaned up from an existing video master. http://www.blu-ray.com/movies/The-Li...5/#Screenshots
Originally, the first eleven Bond films were newly rescanned at 4K and cleaned up. However, because it's so expensive (over 20 films!) only those first eleven films were done in that fashion, whereas the rest were taken from existing video masters and cleaned up from there, retimed, ect. It probably made sense in that case because the films by the 70s were in much better condition anyway and didn't require as much clean up as the films from the 60s. Whatever the case, they managed to really make the films look gorgeous on blu-ray. I pick this THE LIVING DAYLIGHTS as a good example as it was released at the time when the TOS films were made and show that they could look this good if done right. From what I understand, this was also done for the Indiana Jones films. For the blu-ray, RAIDERS was restored at 4K, while the rest were from existing video masters and they all look just as gorgeous.