If you can mod this, I'll start worshipping you!
(And today I've woke up as an atheist
). But we will have to find 3 sects to every religion. It won't be that difficult, but I'm not sure if every religion does have them (e.g. confucionist sects? I only know legalists as their major doctrine...).
Modding this shouldn't be too much of a problem; I just don't have the time...! Basically it could be done in three steps using xml:
(1) Edit the state religion conditions so that one happiness is added for each 'cathedral' (I'm not sure if temples work this way, but even if there isn't room in the curent structure to do it, there are plenty of competent modders here who can add in a 'building happiness' modifier for each religion xml file).
(2) Insert a modifier in the xml file for each religious shrine so that it adds 1 happiness in each city with its corresponding cathedral. I'm pretty sure that the yeild modifiers for wonders would allow for this to be done. Alternately, you could mod cathedrals so that they naturally produce 1 unhappiness, but receive 2 happiness if you civ has their shrine. In that way, there is a net -1 happiness if they exist outside your empire and a net +1 happiness if they are within.
(3) Edit Civic xml files so that 1 happiness is added for each cathedral's favourite civic. This would be similar to the 2 happiness that barracks receive under nationalism. This might cause a bit of odd behaviour (for instance, a Sunni mosque would produce 1 happiness under a catholic theocracy), but given that the civic still matches thier creed would proably be enough to rationally explain that.
As for sects, I don't think that it would be too difficult:
Judaism: Orthodox, Reformed, Kabbalah (?)
Christianity: Orthodox, Catholic, Protestant
Islam: Sunni, Shi'ia, Sufi
Buddhist:Theravāda, Mahāyāna, Vajrayāna
Hinduism: Vaishnavism, Shaivism, Shaktism
Taoism: Quanzhen, Tianshi, Shangqing
Confucianism: orthodox/traditional, legalist, Neo-confucian
You can argue over which would be most appropriate and where, but the point is that there is lots of choice.
About zoroastrism, I'm still very dubious about it. I know they had a lot of influence, but... this faith has almost died. However, I have a simple idea to make zoroastrism, or, as I proposed earlier, a generic solar polytheism, (I still support this idea) become "fading". It simple: make their missionaries, temples and monasteries obsolete with a certain tech (e.g. Theology, or Divine Right). We can make the religion itself to have a low spreading rate, also. That way, ONLY if you built the holy shrine, it will have a chance to continue expanding, and anyway, it won't do it very much.
THere's plenty of religions that fit a similar description (why hasn't jainism been brought up before?) I propose that these religions be manifested through temples that don't require a religion to be present in the city, dont have missionaries, and can only be built by the civilization that has built thier holy shrine. Like the cathedrals of the major religions, these temples would have thier happiness tied to civics, and would stay after other religions have been established, giving the city a religious/mystical background or imprint. Other religions that might fit in this catagory are: shinto, roman/greco pantheism, druze/alawite sects, shikism, mayan/aztec beleifs (Quetzalcoatlism?) etc etc etc.....
. As you can see from the map, it expanded to all the Mediterranean, the area we want to cover, including Persia. Zoroastrism had a big area of influence, but Mithraism spreaded much more further. And it is not that difficult to think in a Mithraist Rome, for example, though it's very dubious to think in the possibility of a Zoroastric Rome, or Egypt.
