You couldn't do that, though, and have it be the same show. They would have to include the SD episode in it's entirety. With TOS, the HD versions are the original versions, just with an HD transfer. With TNG, the remastered episodes would actually be completely different versions, not even really the same show. In other words, TOS remastered is just a new transfer of the original episode, whereas TNG remastered would be an entirely new edit made from the original film.
That's just nonsense. The episodes were shot on 35mm film.
Yes, they were
shot on 35mm film, but edited on videotape. The episodes don't exist on film. What exists are the original negatives, which include takes that were used, alternate takes that were never used, bloopers, outtakes, etc. They can't just make a new transfer of the film the way they did with TOS, they have to actually put the show back in post-production and reedit the the film into an episode (sans music and sound FX, which are usable). How exactly would that not be an entirely new edit?
But again, it's not simply retransfering the film. They have to edit the film into episodes all over again. And no matter how careful they try to be, there will inevitably be discrepencies where something doesn't exactly match up, a wrong angle is accidentally used, a split second shot can't be found, etc.
Nobody is talking about re-cutting the series. The 'entirely new edit' you're writing about will indeed be exactly the same edit as it existed in 480p NTSC video, except in 1080p HD video.
Please explain how raw film that is edited into an episode almost from scratch isn't an "entirely new edit."
That said, seamless branching is still the way to go.
Even putting aside everything else I mentioned, the biggest problem with this is that every time a live action scene would include an original special effect, the live action footage would suddenly and noticeably drop to SD. It would be a jarring viewing experience to say the least.