If KSP combined with Space Engine, we would pretty much have the ultimate space game. Imagine KSP or KSP 2, but with a practically unlimited amount of planets, systems, (and even galaxies!) to explore. It would take interstellar travel to a whole new level. Another added bonus, all of the galaxies/systems/planets would be accurate representations of real locations. If the devs from both games got together, I'm sure they could work something out.