I am but an armchair expert here, but I do think most of what's missing is the complexity of real-life ecosystems and "connections". Having biomes that are substantially large on a given planet and diversity among them, animals unique to each, and some kind of connections between the sparse settlements (even just like 3-5 actual cities per planet would be a start) would be a big difference. It would be a bit less about the 'wonder' and more about understanding the interplay.

For now, all I can see is "optimization" and "system limits on numbers of unique objects for things to work at 60+ FPS".