I had a good experience in Beluaterra with the Bloodspeakers. That was a major reason for wars. An "evil" religion. But, my point and what I tried to do was to let more people add his own ideas. I failed to get enough cooperation from the players. I would like to see the religion with many local deities and local rituals and traditions. Many faces of the same thing.
In Asylon it works because of people trying to do their own RPs about heir own regions and because, different of SA, we are not too much organized at all. We are always flowing in silence and with good RPs. Thing are going well almost by itself. And while I agree the SA needs a religious enemy and even when the CoB can be this enemy, we still have a long way to consolidate our religion and inspire more people into it.
Asylon is a huge realm now. We are formed by some religions, people from different places (many in seek of some revenge) and at some point, duchies that sometimes have more history than the realm itself. Regions descriptions can increase this kind of variety to add more flavor to each duchy and each region or group of regions. Then, you can mix these descriptions and intentions inside the religion, at some point creating the way your people will worship (we already have the Sacred Fruit, after all). Also, we can do it without lose what makes Asylon a kingdom: we are a barbaric realm. We want to loot, to raid and make prisoners. We like to take the spoils. More than ever, we would like to have your food.