I’m just getting into ds9 for the first time and coming to the s1 dvd from the TNG Blu-ray remaster is a big jump. After digging around it seems the reason there’s aliasing and rainbowing confined to the effects shots is that they didn’t apply good comb filtration to the effects which is why the interiors look fine. They apparently used the source broadcast edited tape and thus the series is stuck that way unless a full reconstruction is done.
There is some discussion on LD groups that the LDs handle this better and this have a better looking picture depending on hardware but of course the series wasn’t completed on the format and only had later seasons done in Japan. But they do have pcm Dolby surround…I want too many LDs…