It's pretty common for creators -- authors, artists, bands, etc -- to become formulaic. To some extent, it's just pandering to their estimated audience. Also, t

It's pretty common for creators -- authors, artists, bands, etc -- to become formulaic. To some extent, it's just pandering to their estimated audience. Also, they've typically been working on their first few works for years. And then, if they become popular, they're under pressure to produce more and more, faster and faster. In my opinion, it works best to just write series. You can just use mostly the same characters. Matthew Stover did that well with the Caine series. I gather that he'd been working on it for at least a few years, and had been told that it was unpublishable. So he cut out a first book, and focused on action. Then another, when it sold well enough. And then, years later, after his Star Wars gig, he published the last two. They're basically a metaplot, and collection of back stories, that probably look a lot like the initial project.