Well, with the right coding (from Kov himself, that is), an open source FH is technically possible. However, there are a few things to keep in mind:
Firstly, FH's coding is much more difficult to handle than an IT server. I don't know the details myself, but not just some old Joe could make a new FH.
And second, no new FH servers have been made (nor do we see any in the near future). But even if it did, the original, real FeralHeart isn't going down anytime soon. There is a very dedicated, active, and compassionate staff running this site and game right now.
So, along with any other similar games (Aro'kai, etc.) running about, it likely wouldn't have the calliber to compete so much with a larger game like FH.
This said, it isn't exactly the FH staff's (outside of Kov, since he's been MIA for a year now) choice if it were to go open source. Any other servers would be at the discretion of an entirely different party, and the way they ran their server would be as varying as any IT-based server out there.
So, I understand where you're coming from, and I don't like the idea of an open source FH either. However, it's unlikely, and I don't think it's too much to worry about.