Maybe for the latter seasons of the show, but you can't seriously say that Seasons 1-2 of TNG had anything like decent FX. But then, the FX weren't the only thing shaky about those early episodes... the spandex uniforms and the overly loud synth soundtrack didn't help matters much... Once you get later on, with better FX, the uniform upgrade and more reliance an actual orchestral soundtrack, things improved greatly...
Of course, remastering would only address a few of those 'dated' aspects of the show, but, given how fuzzy and aged I've noticed the syndicated episodes looking on my non-HD cable outlet, it would appear that Remastered TOS totally spanks TNG in the visual department. Personally, I wouldn't mind an FX overhaul, especially for everything before and inclusive of 'The Best of Both Worlds', but even a simple, really thorough digital cleanup on par with what the TOS master tapes got for their remastering would be greatly appreciated...
I don't know. I still say TNG is fine, maybe 10-15 years down the road it could be remastered. I'm sure by then what made TNG great would be considered old school sci-fi. I never really had any problems with 24th century effects.