When people typically discuss worldbuilding, they often talk about doing thing top-down or bottom-up. The former means having a big picture, and slowly drilling down into details that add color and interest. The latter means starting with some specific detail that your story hinges upon, and building out from it to create the wider world of the setting. In putting together a setting, I would say that there is another way to do things, or at least to consider the two perspective: broad or deep.
Broad worldbuilding means that there are a lot of elements introduced, and the person telling a story can pick and choose which of them they want to work with. A lot of roleplaying game settings are designed this way, to give people a variety of options. There are tons of adversaries, dozens or hundreds of locations, all sorts of fiddly bits to play with. The problem is that none of these elements are particularly well developed.
Deep worldbuilding limits the scope. No more than a handful of antagonists, but with more depth to them in terms of goals, motivations, and character development. Fewer locations, but with established and recurring supporting characters and places the protagonists and the audience can build a connection to. Smaller quantity, but higher quality.
Starlight Manifesto was written because I lean more toward deep worldbuilding. There’s no need to add two or three more warlike empires along the border when you haven’t fully fleshed out the one you already have. The existence of multiple merchant trader cultures only makes sense if they’re somehow in conflict with one another; otherwise, for story purposes, they’re interchangeable. Why have a dozen different aliens with the same abilities and objectives, when you could make them the same species and learn more about them each time they appear?
A general argument that I’ve heard about favoring breadth over depth is that people will get bored seeing the same antagonists over and over again, in the same places. My counterargument is that there is plenty of fiction, in novels and television, to prove that wrong. You simply need antagonists with better character development, and more interesting locations. We’re telling stories here, not killing things and taking their stuff.
Keeping the universe of the Starlight Union nice and tight allows you to stick more closely to the themes of hope and humanity. The adversaries all represent something, and the purpose and values of the Peacekeepers don’t get watered down. You get to become emotionally invested in characters because they’re not two-dimensional stereotypes, they’re people. Locations aren’t cardboard cutouts, they’re where people live and work and struggle.
All that aside, I hope you have fun playing this game. Now go beat some bad guys, save the day, and make the universe safe for all sentient beings everywhere!