Michael Piller
wrote a whole (officially unpublished) book about the scripting process for
Insurrection, and it's revealing about the mentality at Paramount, the TNG cast, and the ST production staff. Making a better movie wouldn't be impossible, but it'd be a tall order. (I can't link directly to the book "Fade In", as Paramount occasionally pulls it from the internet and my current link is now dead, but a Google search should turn up something if you're curious.)
1. Because of the success of First Contact proving he was a bankable star, Patrick Stewart got an associate producer's credit on Insurrection, and a hand in the scripting process. Patrick Stewart wanted to flex his action movie chops, not his dramatic ones.
2. Insurrection was intended from the beginning to be a counterpoint in tone from FC, which was felt to be too dark and un-Treklike. In its earlier drafts, INS was basically a riff on Heart of Darkness, and was a fair bit grimmer. The Dominion War originally drove the need for the "medical mineral" that eventually became the fountain of youth device in the final script, but that element got eliminated. Rick Berman wasn't a fan of the Dominion War plot in general, and consulting with DS9's head writer made the matter moot as, when Insurrection would hit theaters, the war would be winding down on the TV show. Picard would spend half the movie tracking down Data and killing him, but that was vetoed for its darkness and turned into the short sequence we got. The idea of the Federation actually going to the dark side was
incredibly controversial among everyone involved in the movie, with Stewart even making a joking aside about Gene Roddenberry spinning in his grave. The idea was kept, mostly because Piller was trying to salvage as much as he could from his previous drafts due to lack of time for a fresh start, but it got watered down.
3. All the script problems and plot holes people commonly bring up about Insurrection? They knew about them. Brent Spiner in particular gave Piller a laundry list of questions about the script that's practically out of a Plinkett review. Stewart even goes so far as to cite specific episodes that had covered the movie's themes already. Piller just couldn't iron them all out, partly because of time constraints before filming started. If there was ever an unclear point, or something ambiguous where it wasn't clear the audience understood why something was happening, Rick Berman stuck in technobabble dialogue to explain it. Piller talks about how even Berman would complain about excessive technobabble, but then regularly call him from the editing room to come up new technobabble explanations for why something was happening on-screen.
So making the TNG movies better than OTL? To do it, you'd need to shake up both the ST staff and the suits at Paramount. Both were of one mind about what ST was supposed to be like, and didn't want to deviate from that.
Generations was made with a long list of demands from Paramount from the very start:
*snipped*
There's also the factor of split commitments. Moore and Braga were writing the script for the TNG finale "All Good Things..." at the same time as the one for Generations. Moore admitted in some interview, I think his long tell-all one with IGN back in the early 2000s, that the finale ended up getting the majority of their attention, and that he and Braga weren't sufficiently experienced at that point with scripting movies.
Having someone other than Moore and Braga could likely help smooth out the script, despite the demands by Paramount you list.