I'll make as many nebulae as I can. As long as I focus on making one star cluster at a time, I should be able to keep the content solid and avoid holes where there's just nothing to do or see. Also, this method is very handy, because I could release entire new star clusters through the use of add-on plugs in the future, with new side-missions and all that.
By the way, transit between systems and clusters will be different than usual. Instead of making long voyages with countless numbers of jumps, there will be an "impeller projection" network that facilitates rapid travel (hypergates, in practice). The interesting thing about spatial impellers is that their principle operating factor theoretically enables them to jump anywhere in the universe almost instantaneously. The only limitation is the starship computer hooked up to them. Because of things like gravity wells, debris, rogue planetoids, black holes, quarks, quasars, etc. etc., a navigational computer has to do MASSIVE amounts of computation before safely allowing a jump. While the engine could technically propel a vessel to a neighboring galaxy with minimal effort, there are no known star charts of the target destination and no calculated graviton point to jump to. Studying the obstacles over such a distance would take centuries. What the impeller projectors provide is pre-calculated coordinates for starships within broadcast/reception range, enabling otherwise limited ships to jump inordinate distances. Really, there's no mechanical impeller feature in the stations themselves, just massive computers and sensor equipment.
