1) There doesn't appear to be a way to input Age into a custom stars.sc script. Could that be added please? (seems odd because that's a rather important aspect of a system. So far it looks like it's just set by default to 5 billion years, while planets without an Age parameter seem to have something random that's unrelated to the age of their star when they really should be similar if not the same).
2) A way to tell SE in a script to procedurally generate Asteroid Belts in a system by defining a range of semimajor axes and a number of asteroids (e.g. InnerLimit, OuterLimit, NumAsteroid) would be nice, rather than having to calculate and enter them all as individual asteroids.
3) A way to tell SE in a script that it should generate moons for imported planets (or not, via 'NoMoons true'). It doesn't look like this exists at the moment - which is odd, since procedurally generated rings are present.