Well here's the thing with TNG; the amount of raw material that is available for the show is so much the company that did the TNG DVDs wanted to do a full seven disc set of nothing but extras but Paramount wouldn't go for it. There's THAT MUCH material in near pristine shape; and that doesn't even include the original elements which are preserved even better than the original series.
The only thing holding it back is if it is worth it financially for CBS to do it, and since TNG sold so well on DVD it's almost a no-brainer. The 25th Anniversary of the show is coming up in just a couple years so it would be the perfect time to do the BluRay re-release of TNG with remasted video and effects.
You'll never see DS9 or VOY remastered the way TOS was, but the chances of TNG happening are very good.
Also the new release should be awesome. CBS does an amazing job on their TV DVDs, better even than what Paramount did in the past. The TOS Remastered DVDs/BluRays along with the Twilight Zone Definitive Collection (done by Image under supervision of CBS) are fantastic and are even better than the initial Trek DVD releases.