DS9 currently has the exact same lo-res video transfers that TNG had. It will benefit from a remastering every bit as much as TNG has.
Actually, you're completely right, I just rewatched "Emissary" today, and I'd have to agree. It does need some work. I hadn't rewatched DS9
in so long...everything looks better in distant hindsight, doesn't it?
On a minor note, one thing I picked up on today that definitely needs attending to is this: in the scene where Sisko meets with Picard in the Enterprise's conference room, and you can see Bajor from the window, and it clearly looks like a large prop hanging just outside the window. The shadowing looks awful, and the planet looks like paper-mache.
And then it began to occur to me how much graininess in the image there was, and how "model-y" the ship models looked. It really could use some cleaning up.
It started a chain reaction in my head where every Trek episode I watched today in my personal little marathon started to look terrible. I watched TNG's
"Timescape" and began to notice how much all of the actors who were supposed to be frozen in time are jiggling a little bit. If they don't fix that in the eventual remaster, it's really going to show in HD. That's when I knew I needed to take a break and go eat some Thanksgiving food.