A good miniature shot should look real. A good CGI sequence should look real. Only our knowledge that there is no real starship should betray the effect and as amazing as the filming models were, there's not one shot of it in TNG that would stand up to either today's CGI standards or current viewer expectations.
No offense, but I call bullshit.
TNG's model work was fantastic in most cases, and extremely well done. I've watched many an episode over the years, and I think the visual effects hold up quite well. Sure, there's a lack of certain things, like the ability to show tons of ships when an armada is supposedly going into battle, but what is on the screen looks good.
Frankly, I find a great deal of the televised CGI work done in the later years to be quite wanting in comparison to TNG.
Sure, TNG's visual effects will need to be re-done if they want to do an HD release, simply because they were shot on videotape and don't have the resolution necessary to support HD. But I don't think viewers would otherwise have any problem with most of the visual effects from that series.