Have you thought about including angels in the mix? If you can have demons for the bad guys, why not a celestial host for the good guys? These could either be heroes, produced by a building, or a religious affliation.
Having played around 5 games on this mod, I do like the feel of the open ended nature of the tech tree, and the fact that it does allow more variation than the vanilla version.
Having played around 5 games on this mod, I do like the feel of the open ended nature of the tech tree, and the fact that it does allow more variation than the vanilla version.