Star Trek was shot on 35 mm film with the intention of being displayed on NTSC technology. Making an HD version is easy; you just run the film through your digital scanner and click the HD radio button instead of the 480i radio button. The problem you run into is with the optical shots; they've got all kinds of dupe grain and matte lines on them. This was visible, but not too troubling, on NTSC video. But in HD, they make the shots practically unwatchable.
Why remaster the show for HD? There's a crazy big market for Star Trek right now. There's at least three blocks dedicated to Star Trek on my cable package; Star Trek Uncut and Star Trek 2.0 on cable, and Star Trek "remastered" in syndication. Star Trek packages will become more valuable over the next couple of years as the hype machine for Star Trek XI gets into gear. And then there's Shatner; William Shatner is a popular actor right now due to Boston Legal and his tongue-in-cheek public persona.
So, having an HD-ready version of Star Trek for syndication (and later optical disc release) is a no-brainer. But what do you do about the visual effects? I'm sure the original elements are long since lost; they cannot be recomposited like Lucas did for Star Wars. So they have to be recreated. And in the process of recreation, a few creative liberties can be taken to reduce the number of stock shots. This is very much in the spirit of restoration that Mike Verta wrote about on Star Wars Legacy, and the complete opposite of Lucas-style revisionism. And that's why I love it and why you should love it, too.