The big problem with religion is that to make it fun and exciting it had to have power. In order to have power players have to be willing to subjugate their characters to its authority voluntarily. And they have to be willing to use the game mechanics power given to them by their secular positions for the benefit of their religion, even in defiance of that secular organization. It's very hard to find people willing to do that. We had it in the early days of SA, and it rocked.