I sincerely appreciate the feedback! I intentionally did not give much in terms of the details of the cult because I wanted it to be more of a prompt; something players could build from, especially since they could pick any kind of book and this might inform their cult's style. I also felt that a GM was good thematically, giving the whole idea that there is a divine being, but no one is getting it right, and everything is kind of up to their whim... just thought that scenario was a bit funny.
I certainly think that you're on to something though, and that the game could be modified to leave the existence of a divine being out of it, and have it be a GMless game. All in all I think you're possibly envisioning a game that would have a more serious undertone, while I was going for a little more silly (with the expectation people will choose silly books).