Starshatter has a lot of unique depth for me that can't be found in Freespace (without a lot of work, anyways). As I recall, the framework was all there for having a complete multiplayer fleet system where players could assume various roles (overall C&C, cruiser command, fighter wingleader, etc) in combination with other AI ships, all in real-time.
If this could be set up in a proper co-operative setting, this sort of thing would be VERY appealing to me. Being able to play this at a LAN party with one player managing carrier control, strike package planning and the overall scenario theatre, with another handling actual capital ship command and yet a third leading actual fighter / bomber ops in support of said capital ships, all in this gigantic multiplayer dynamic campaign setting against the AI sounds like an insanely awesome co-operative experience. To this end, I'm absolutely interested in any progress made with the source code and hope the game is able to reach a state where all of this is possible eventually.
Yes, I definitely see the appeal of Starshatter in contrast to Freespace.