Probably no chance of happening any time soon but I was thinking about exploration and the unknown of star trek. Id love to see a new sector block opened up and everything in it is unannounced just waiting for us to go and explore.
So there is no contact to get missions from as you have never been there before to meet anyone, just a dozen systems and everyone has something different. It could be a story missions, a fleet action, patrol missions, a social zone, a group of side quests, anything but the only way to find out is to just fly up to a system and enter it.
Then once your inside depending on the mission you will either be presented with an obvious situation that will start the mission or perhaps you will have to go look for them. Bases and derelict ships dotted round, unknown alien cultures to talk to, trade with or fight.
They have slightly started this with the changing patrols in orelius, and the side quests like satellite repair or the ore transport, and in eta with the two missions you have to find find the freighter and help the ferengi outpost. All of which I think is a great start but really kick it up a notch. Maybe state that its an area on the edge of federation or klingon space that has never been explored before.
Whilst eventually it will lose its appeal as you can only explore something new once, I think it would be super cool the first time you enter this uncharted region. (And no spoilers from the devs).