This could be very expensive, as DS9 has some complicated VFX. Not just battle scenes, but things like Odo's morph will have to be redone as well. Hopefully, they'll have access to the original negatives to make this alot easier. Even then, this will very time consuming and costly.
I can't see DS9 or VOY getting the remastered treatment any time soon, especially as they don't have the same popularity and viewing figures as TOS & TNG.