I'm working on the religion section for worldbuilding, and giving a lot of thought to it. What sort of a world do you get when the reality of the Divine can be proven? When the deity or deities make appearances, answer prayers, and otherwise demonstrate that They do in fact exist? Faith ceases to be a concern. Why do you need faith with a deity that shows up for dinner? On the other hand, what sort of a relationship do the people have with these actually-present deities? How does Their existence affect daily life, the course of history, and all that? What constraints are on Their powers? The deities have to be constrained, after all, or the core concept of the game, player agency, goes right out the window. I've got some thoughts on this, and am working on getting it all written up. I'll post it as soon as it's gotten past the first draft stage. 

Getting the world built, or at least a solid foundation laid, seemed important enough to the project that I've diverted from mechanics and more granular tasks for a while. More on this story as it develops.