While most here have not directly answered the question, the indirect answer is quite clear, Derek. Would I buy Freespace 3? Yes. Would I buy it if you made it? Not a chance. I've tried all of the Battlecruisers and Universal Combat. None of them held any interest for me and most managed to piss me off just in the menus alone before I even got to PLAYING the game.
Freespace is an arcade-style space sim franchise like the Wing Commander's back in the day and I highly doubt you have any interest in maintaining that. My recommendation, if you already have the rights is to sit on it and look for a different development studio that wants to buy it from you. Bump the price up from what you paid, make a few bucks and let someone that is actually interested in making a real Freespace game create it.