What might be a cool product (I’d definitely buy it, anyway) is a series of “campaign framework” books as companions to each quadrant book.
I’m thinking about something primarily with GM advice on how to run a campaign in the style of each of the series, looking at how you’d set up such a game, considerations for what ship you’d give the players, possible areas of trouble to watch out for, etc.
For the Delta Quadrant, it’d be a book on how to design and run a Voyager-esque campaign where the players are stuck on the other side of the galaxy. So there could be rules on downgrading the ship rather than upgrades (reflecting damage repaired by incompatible or lower quality alien parts), on integrating aliens into the crew, alternate rewards for the players since character promotions and ship upgrades are not going to be available 50,000 light years from home, etc.
And there could also be advice on how to tie in themes from history and myth - how can you draw in “The Odyssey” as inspiration for your Voyager-style game, etc.
And also ideas on different ways to structure the campaign - as a quest (find these three ancient alien artifacts to build a makeshift transwarp generator and get home right away), or as a straight-line journey back home, or other possibilities (how to handle it if your players decide getting home is impossible so why not create a mini-Federation on the other side of the galaxy).