Years ago I made a space game that was basically, Keep Talking And Nobody Explodes, but with spaceships. I made it way too complicated and basically only I could play it, but I've often thought that it was a good basis for a game if only I made it less stupid.

I cannot believe nobody has made a space game since, where being the master of your ship is the whole goal. Basically Euro truck simulator in space. One of the nice things about that game is that all the gamey stuff is just handled by menus so that you can actually get to the experience without having to wander around a supplemental environment that doesn't really add anything to the experience.