Should DS9 get Remastered - yes it should, starting right now.
Personally I wouldn't buy the Remastered version until I am rich enough to afford a 60" TV...which wouldn't be until years into the future.
Additionally, I certainly wouldn't pay the $130 USD or more that Paramount would probably charge per Season
for the the first 3-5+ years that DS9 is sold in HD.
So yeah, they should get their butts in gear and start Remastering DS9 right now because even after they release it, it will still be years later before it is priced reasonably enough to buy.