I know this is an old post but a very good point indeed.
Religions do not seem to be a very popular thing on BT, because most of the players go there for war, I assume.
As Noldorin stated above, The Order of The Golden Feather was quite active back in the days, being spread almost over all of Thalmarkin and maybe even some in OG/AA. It collapsed though, due to no elder positions being ran by priests anymore.
Anyway, it got resurrected more recently, by a few people in Thalmarkin including myself. I have been running it but I sense it is quite hard to 'sell' it to the other nobles. It takes time and gets quite boring for most people. (Could of course also have to do with its content). Also you need a lot of imagination to keep things alive and get things going, which I currently lack abit I guess. And I doubt there are many people wishing to actively play priest characters on BT with all the fun going on right now.