The Council of Esus is not meant to be good to convert to. The whole point is that you can run it effectvely alongside another religion.
Wich somewhat breaks the point for the Council of being a religion and not some guild or something like that.
What to you gain through choosing CoE while running FoL alongside it wich you won't get when you take FoL and let CoE run alongside it?
Story-wise the first would be that the Council is hiding behind the face of another religion, the second means that the Fellower are allowing a few Council members to operate in their cities.
Just a few ideas wich could be added for a 'little' stronger CoE (i'm not sure if it should get any stronger... but yeah):
-People who choose CoE can also choose between the civic options of the other religion, making this option/religion up as a facade and giving some bonuses for CoE followers (Svartalfar would for example be CoE followers, but could still use Guardian of Nature wich would fit their theme i think).
Therefore it would also be nice if instead of CoE the player/computer would choose this facade and only this facade gets shown in the diplomatic screens and such.
-Maybe a bonus for CoE-Units (units with the religion, not the special religous one) to attack cities with a high crime rating (or is this rating now gone?). Or the crime rate adding up as defence bonus for CoE-Units defending a CoE-city.
-A high citry crime rating could also lift the fog of war for CoE-civs instead of CoE existing in this city.
-Remove the disply of what units are in cities and only open it up through intelligence, wherefore CoE could open up a few extra options.
-Espionage/Sabotage options without having to send a unit to a city.
-If a CoE City gets captured from a player who has the CoE-religion some Nightwatch/Thieves or whatever could be spawned (but i don't really like this idea
).