The Wormhole wrote:
If you want (what I think) is the real reason: TPTB probably felt that since the Constitution Class Enterprise was a "hero" ship, there can't be another ship on screen that looked like it, since it could cause some confusion among the audience.
But that's just my two cents worth.
I would try to argue that no one thought the audience would be confusing the ship on screen with a "hero" ship when they showed all kinds of Galaxy class ships on DS9, but then considering how often I heard people say "is that the Enterprise?"...
One must also consider the first time DS9 showed a Galaxy
class, it was to blow it up to make a point. Afterward, all the ones we saw were after the Enterprise-D
was (grumble) destroyed and it was technically no longer a Hero Ship.
TNG had overlap with the TOS movies, which is probably why they avoided showing operational Constitution
class ships - even though it was 80 years later, they were still making the movies with them in them. Which in turn probably explains why there was never a CGI model made of it, which is why we didn't see them in action on DS9 or VGR.