I think it would be very interesting to have a nonlinear game, somewhat similar to the play style of Mass Effect. I mean this in terms of being able to travel from planet to planet and explore them. THis game would be without a leveling system though, so no RPG level progression or stats. The game could be third or first person on foot, but I think first person would be more interesting.) It could have a major story, which would involve STF and whatnot, and it MUST have some GINORMOUS battles. But there would be plenty of side quests, like SKyrim. You could respond to distress signals, engage in commerce, fight off pirates (or pirate yourself) etc... I'm not sure if ship combat could be done well in fisrt, so perhaps third person for ship combat. You start off in STF as a lowly officer, and advance to admiral, giving Starfleet itself orders and conduct diplomacy and start wars. (the AI would control everything but yourself and your own ship) Or perhaps you could become an extremely notorious pirate or mercenary.