I get the impression that FS has very useful tools for evolving a story and the universe it's set in.
...In which, I think a "loose" approach is quite good for the tools available. Give the character a name and gender, fine. However, I think the dynamics of the character should be reflected by the FREDed nuances of the support cast - this will make for tougher mission design, though. What this allows the player to do is still "feel" what he/she might want the character they're playing as to feel, while not specifically being told
what to feel.
Adding in player character dialogue doesn't hurt as long as it doesn't overpower what the player might naturally feel.
If you can balance those two aspects in a campaign, you can really bring a story to life. I think Transcend followed this pattern to a substantial degree at least in terms of the latter point. You
felt like Sunder Marcel - you became that character. I think that Ransom did a better job with making you feel like the character in Transcend than Darius did with Samuel Bei in BP:AoA, in all honesty, for the mere reason that Ransom
did not impose any feelings upon the player.
The player was instead invited to explore their own feelings in relation to the events presented. If you must have a character-driven story, I think abstracting Transcend's methodology is a superb route.
Applying the former point - campaign dynamics - is the masterful element which is truly difficult and elusive. That has the capacity to literally make the campaign different every time, which is something fun to think about but a real dragon to dual with. Dynamic characters are a step beyond that...
Empty, long, or mundane missions are superb opportunities for character development.
A snippet of that three-hour patrol. Derelict's nav-beacon placements within the asteroid field. Flying the landing pattern about the destroyer... Action isn't everything. Going through training, boring (and even uneventful) escort missions, and the like give a sense of being within the world, and because your wingmates will be just as bored as you, there is the time to develop the personal side of the story. This is something BP does exceptionally well.
Those are my thoughts on the matter.