more pleasing color that blends nicely with the dark background
I think the green color is fine, plus we don't want it to blend iNTO the background.
And taking a screenshot while being able to see how the planets/moons orbit their host would be cool.
Why not just leave the orbit display on and take a screenshot?
Another thing which would be useful: It is to have an option that makes the orbits automatically faint away when you're close to the surface of a planet, so you don't have to make multiple visits to the settings when descending down to take a picture and ascending up to view the orbits again.
Or just use the shortcut key,'o'.