In addition to getting your own balance and physics, a good way to attract Nexuiz players to it would be to get a server with your settings up. That way you can tell Nexuizers "You can still play Nexuiz in Xonotic, plus better graphics! Join <server address> to play with more familiar physics and weapons"
Also, if you work on a DSX, try getting in touch with akari. He made one for 0.1.
Creating an alternative balance is a way better alternative to creating a fork; you have support behind the existing Xonotic community, you'll be able to maintain the balance by yourself (mostly), and it would keep players playing the same game, even if on different servers (realizing that not all of the nexuiz players would have moved to Vengeance had it been created, mainly because of the bad taste left from the initial split/fork/illfonic).