If Volition were to take the SCP, optimize and bugfix it and make a new campaign for it, I think they could make a profit. Volition making another Freespace is akin to Blizzard making another Starcraft, on a smaller scale. I suppose the question is, "Is this the right time?". Things have been going on a trend towards being more personal and in-your-face than space action sims.
However, Freespace 2 (from what I've read anyway) is pretty widely respected as being one of the best space sims of its time.
So I think THQ could make a profit from it, especially if they marketed it right. (Let's put a double emphasis on it, shall we?) Considering most people haven't even heard of Freespace 2, my own impression, a good release could net the would-be buyers of Freespace 2 that never were, just because they didn't hear about it. For those desperately seeking Freespace 2 on eBay, it could be a godsend.