Yeah, why I don't see the immediate need for a remastering job on DS9 (I'd hope they'd do TNG first because it definitely needs it more!), there were reused ship shots (i.e. it seemed that the same 11 or 12 ships were always in orbit around DS9!).
There were others too, and as was mentioned, I think the earlier seasons are in much more need of it than the latter ones.
brought up the best point so far I think: Odo's shifting effects. They were utter crap in earlier seasons! To be honest, I was never satisfied with them at all (even in season seven). I realize they are difficult effects shots, but I'd love to see them redone.