I know you can mess around with all the different settings (making everything more rare and spread out) to give the impression of a more expansive universe. But, I think it would be cool to have a "Scale" slider at the beginning of the game. This slider would automatically adjust all the other settings to make the universe appear more/less expansive. One of the key things I would like this slider to do, which cannot simply be done by messing around with the other settings, is to make the solar systems more realistic and interesting when the expansiveness is set to high. Basically this would make each tile represent less space, so that the map in general is more zoomed in (or zoomed out if you prefer). I personally like playing on maps where its difficult to get to another star, but each solar system has a lot of planets and things to do. I envision this setting designating say 5-10 hexes around a star as its "solar system" instead of the current 2-4 hexes. This would cause more interesting placement of rocky planets, asteroids & gas giants. And even possibly enable them to orbit! This would also increase the territorial-ness of space warfare. You would defend an entire system vigorously, or else your enemy would gain a valuable foot hold. I know this is already a part of the strategy, but I believe it would be enhanced by the option to increase the scale.
Alternatively, a specific setting that adjusts the size of each solar system would also do the trick!
Thoughts, Concerns, Questions?