- Backdrop Asteroid belts
- Backdrop Orbits circles
To add some more things in a solar system. In other words, you see things, but you can't reach them. ie, when you zoom in a solar system, you'd see a ring of debris around the star. The random map generator could also be set to generate asteroid planets INSIDE this backdrop asteroid belt, adding to the realism, since current games have asteroid belts everywhere, without any logical position.
Planets orbits lines, while not having planets actually move, would simply add again a more "star system" feeling, than the current board game feeling. This way you'd actually know you started the game on the third planet of the system, and not the planet with an asteroid to the left, an ice planet up and a volcano right...
Just to add to the touch of an already impressive game. These kind of things should be easily added to a patch, and I beleive they would only involve some more icon locations. (The game seems to be based on sprites a lot, as I found out planet atmosphere are actually overlapped pictures of a semi transparent circle

[found your secret!!] )