432 is correct (thats 480p NTSC dvd standard) minus the black bars. It's too old to have a higher resolution. It would require remastering all the material (if it's even still available)
t was filmed in a format that did not lend itself to remastering like STNG did
Well that does imo fall a bit under "too old"
I am by no means an expert on the topic, but STNG is older than DS9 and it was remastered so while I think you are right in that age plays a part in this I don't think it's the only thing that matters.
I am just thinking back to how some older titles look great in 4k remasters while some that are significantly newer look worse. I recall specifically that "Unforgiven" from 1992 in 4k looks beyond amazing.
From what I understand it was filmed in a format that did not lend itself to remastering like STNG did. I am not sure if that means a remaster is impossible or just too costly to be profitable. I bought STNG on Blu-Ray (it was a pretty expensive), I would do the same for DS9 if they were able to do it.
Not so, it was filmed on 35mm film like the others. In fact the recent fan-funded documentary "What we left behind" included a number of scenes they paid to properly remaster (in full fat widescreen no less - and it looked fantastic!). Unlike TNG, the chief cameraman for the show made a point of keeping stupid things out of the entire field of view at all times!). Scanning and cleaning up the original negs was easy, but redoing them special effects is harder - DS9 used a lot of model work, but started using more computer effects too - and these have to be rebuilt from scratch. Apparently the main problem isn't the lack of good quality original film, but the money required (it takes a lot of manpower). The TNG remaster was popular with the fans, but didn't sell widely enough to recoup the cost, so they stopped there...
Talk to the Klingons, they filmed it.
Another crappy thing about not getting a remaster of DS9 and Voyager, is that they are Variable Frame Rate. Some of the special effect space scenes are 30FPS and the rest of it is 24FPS. I think some of the effects were done in the UK and they elected to go with 30FPS. After encoding with Handbrake (even using the VFR setting), some players have a hard time with it. Some of the space scenes are not smooth at all. They look like a frame is missing about every half second. I wish we could get a remaster at some point, but according to Paramount, the remaster of TNG took an incredible amount of work digging through tons of old footage to find what was needed. There is even a footnote on the back of the remaster BD about 3-4 episodes that have a few seconds to a few mins of SD because they were unable to find the original footage. Hoping that one day a remaster will happen. Totally sucks to let such iconic series die on DVD