You know what I would love? A mix between Iwar2( pirating), and the Darkening (trade), in Sol only. You, just one system, but a detailled one, with gates at all strategic points ( AKA near large stations). and the ability to land on planets (no need to be able to go into the tamosphere, the privateer2 way was way enough for me, maybe a cutscene using the game engine would be great tho).
And randomly generated missions to top it all, for those who don't like pirating or trading, they could play as a mercs (like capture the crew of that ship and bring it into the Moon orbiter station, stuff like that).
You'd have a big ship, kindda like in Iwar2, but not ubberpowerfull corvettes with lots of guns, all ships would have no shields, and machineguns, stuff that can nail another ship in seconds (fast and furious dogfights), and you can undock a fighter, a friend/copilot would handle one of the ships and you the other. voila voila.