Either 1) What YOU would make a campaign of. It doesn't nesacarily have to be post-capella, but keep it Freespace. What part of the FS timeline/Universe would you explore? What would it be like, etc.
or 2) How would YOU end the FS story/timeline. Bassically, tell us what you think FS3 is/would be/will be/whatever. (could be FS4, FS9, whatever)
Project leads, if you don't want to give anything away from your campaigns, then just give a different timeline or campaign idea you've had (everyone has tons of those

Go.