In my opinion, avatars have been added to play a balancing role, preventing ruling clans from becoming invincible.
Could other solutions have been adopted? Of course, it all depends on the type of gameplay you want.
For example, on private servers avatars are not necessary, because the balance is guaranteed by the limitations and rules of the servers.
This concept of religions as a weapon, is redundant and concerns the gameplay and lore set by Funcom on the official servers, Funcom decides to add the avatars and makes Conan say that they are not real gods, why?
Because Conan worships Crom and Crom is the source of his “natural” willpower and all sorcery is evil? This is the consideration of the sorcery in Howard’s works, but this is not applicable for the balancing of a game.
If I want to play a necromancer, the game has to let me have the same possibilities as a barbaric warrior, but on a different path, but this is not lore-friendly!
So I don’t know how Funcom wants to add magic, after all, as they added the avatars, they can come up with anything.
Magic and supernatural beings, and therefore the worship offered to them, are one thing, but anyone who has the license can do whatever he wants, including avatars, a D&D style magic-science, or at last Spider-man and Conan together (Marvel).
Many players want a magic system like the one from Skyrim, instead, other players want a lore-friendly magic system. What I hope is that Funcom will implement some sorcery new mechanic, so modders could create more variants based on a vanilla system, then everyone will play the lore he prefers.