I disagree in that “big picture” isn’t really a necessary ingredient. the OT didn’t really have one, either - part of the reason Lucas could blow up Empire the way he did is because he didn’t have any real big picture. He just made something up and stuck it at the end of his script and then had to try and figure out how that was going to work in Jedi. And then how he ended up having it work was ALSO something that didn’t have any big picture planning behind it. Same with the Prequels: The only real “big picture” was the status quo at the beginning of Star Wars. But the way he got to that status quo had no solid throughline at all, and that’s because he just made each story up as he went. Even the parts that he’d been telling us about for decades by that point weren’t the same when he finally got around to writing them.

Of course, those are semi-negative examples that sort of prove that a “big picture” might actually be necessary, but there are countless other examples of movies, film series, tv shows, books, etc. whose greatness is unquestioned, but whose creative paths were absolutely not mapped, or pre-ordained when they began. In fact MOST great stuff we all like and have copies of on our shelves wasn’t created that way. The idea of the “Big Picture” being a necessary element is mostly a myth, and it’s mostly a new one, created in response to TV fans reacting poorly to LOST and Battlestar Galactica. It’s less an actual recipe for making great art, and more like a security blanket for consumers so they can feel good about investing all their time and energy into following along with a story and feeling like they won’t be disappointed at the end. Since almost everything that causes someone to BECOME a fan was created without any serious “big picture” in place before it was started, the idea that the “big picture” is a thing that’s desperately needed doesn’t make any sense, unless you’re solely looking at it as an insurance policy.