Sadly NCsoft tends to like to hold on to all their rights for old abandoned games. There are 3 NCsoft games that I can name off the top of my head that I think never should have shut down... Tabula Rasa, Auto Assault, and Exteel. I miss all those game,and they will never come back cause NCsoft don't want to sell the copyright.
I still have no idea why Exteel was shut down.
But on topic... How does Tabula Rasa compare to Defiance? They seem fairly similar. Have you looked into it?