Would Insurrection - or, let's say, any movie that followed First Contact - have been stronger if the story had derived from an idea or character introduced in a TNG episode? That was the case with First Contact (and of course with TWoK in the case of the first series). Given the results, it seems to have been a good idea.
So was that idea deliberately resisted in this case? Was the impulse to follow FC with a more pastoral movie with lots of location shooting so strong that the attempt to do an independent story a la The Final Frontier was the inevitable result?
Some months ago I read the Piller book online, and I found it more interesting than the movie in many ways - but I don't recall whether he addressed the independent story versus sequel-to-an-episode choice.
I don't know about the whole "sequel vs. stand-alone" issue, but INS was a conscious decision to make a quieter, less epic action movie than FC. Their attitude was was why try to top FC in that category, because they'd just fail.