I think its not just the overload factor. GoG was too dry, just a list of spells & rules with little flavour to go with it. One of the best things IMHO about Cults of Prax was the Travels of Biturian Varosh (and the account of the Dorastan war in Cults of Terror).
When I was 13, all my characters wanted from a cult was powerful magic and a mandate to slaughter. Any kind of background was an added bonus. Now I'm older (if not any wiser) I have a differing view.
I don't think the proliferation of cults/gods is a problem, you can always ignore what you don't like. I think its gets difficult when the multiplicity of choices outweighs the richness of the background.
I think the balance should be to present background (fiction, histories etc) which leads players to make decisions as to cults etc, based on what appeals as an example of play, rather than present a list of options and say "pick one with the powers you'd like". For example, ask someone if they want a character who has the sorts of adventures Biturian Varosh does, rather than as if Path Watch is a feat they want.
Andy
Powered by hypermail