I suggested this a while back to change the colours of land, sea and sky. Before someone said that THEY had suggested it a while back to change the colours of land sea and sky which they then had someone else..-
Meh.
I believe a colour editor is an easy next-feature target. It doesn't sound too complex (and of course it doesn't have to be...) yet it creates a whole new bunch of activities, combinations, integration ideas and opportunities. I think anyone would have a lot of fun with this. Even if it isn't realistic, so what? The fact that there is a so many still unfinished features and features that haven't been released yet and even features that haven't been thought of, makes the whole simulation a bit unrealistic. (lack of roche limits, lack of proper galaxies) But the vision of Universe Sandbox 2 in a few years makes up for all that. The devs are doing a really great job