I'm not quite sure something like that would work for a simulator like this. If it is not already apparent, the main purpose of this game is to be a gravity simulator. Sure, Dan and the team have done climate, stellar evolution, as well as tidal heating, but it all fits.
This game simulates on a massive, macro-type scale. The stuff seen in Space Engine focuses on smaller scale, so to speak. Sure, you can explore any planet you want, from orbit down to the surface, which is still huge, but its not applied in the same way as Universe Sandbox.
It would be awesome if they put something like that in US2, but getting it to work sounds hard. And besides, a feature such as planet exploration might detract from what this game is really about.