Hmm, well since several movies are being mentioned here I'll chip in with MO.
In general, TNG movies were severely hurt by Paramount's complete lack of faith in TNG being a successful movie franchise, and therefore only providing shoestring budgets for the TNG films. (Fuck you Paramount!

) But they did have faith in the JJ reboot and forked over the cash for that one, and look how it turned out (singlehandedly resurrecting the Star Trek name, albeit as a different being to the original).
Money problems aside though, IMO the biggest problems with Insurrection are the following:
1. The whole story is booooooooring! The premise is that Picard and crew are rebelling against the Federation to save people that need their help. This severely falls flat on its face when we find out that these people not only *don't* need to be saved, but also don't *want* to be saved. They come across as arrogant assholes who are not worthy of the sacrifice the Enterprise crew is making for them.
So this causes the problem that you don't care about their plight, and you don't care if Picard and crew are successful in their quest, so the whole thing is dreadfully boring to watch, because you as the viewer are not engaged in the story at all.
It doesn't help that due to the shoe string budget, all they can do for 70% of the movie is run across California hills and cave sets.
2. The lameness of the jokes. I have no idea who's idea was it to write boob and zit jokes and actually think they are funny. Didn't they have test audiences to gauge the reactions? I have to say they probably didn't, and thought their shit didn't stink.
3. Gimmicks like the joystick. Shit that was a cringe inducing moment. What were they thinking?
A typical audience would think of this movie as simply mediocre, and nothing special at all.