Admittedly I haven't personally seen many of the TNG two-parters:im still working on my Deep Space 9 episodes.
That established, I can think of STANDARD LENGTH TNG episodes which are ahead of ALL of the movies in every respect.
I cite "Who Watches the Watchers" as my example. That episode succeeds where Nemesis, Insurrection, Generations, and First Contact failed-on the fundamentals of telling a good story.
That's the core foundation of Trek when its all said and done, namely the use of believable and identifiable characters using futuristic technology and their sheer wit to solve problems in a funny, entertaining and plausible
The movie making teams forgot about that when making the TNG features.They used caricatures of the complex TNG characters, stuffed them into stories a 10 year old would call stupid, and hoped the special effects would induce memory blackouts so the audience wouldn't remember the sorry script.
With the TV series, the writers couldn't afford to produce schlock at the season finale.I chalk up the quality difference to the fact that if the movies failed at the box office, no worries, Paramount would eventually
re-make another Star Trek. So what if the movie writers produced Lucasfilm-grade schlock? Paramount would never abandon the franchise;worst case they'd just get someone else to make the next movie, so the only thing the Star Trek TNG creative time had to do was make their movie well enough to not get fired.
The TV show on the other hand was NOT guaranteed by any stretch.The studio wouldn't abandon Star Trek movies , but one bad TV season finale and the jigs up. Since the series could be cancelled by the studio at the end of a season, the writers and creative staff got their sh-t together for the TNG two parters;because it would be the bread lines for them if they put up schlock for a season finale.