Does anyone build these rituals? IMHO they are too expensive to have any effect, you really have to have an incredible production to make it worth the investment. Actually both civilizations are supposed to be able to influence the AC, but at 600 there are many better ways to do this. That's why there should be some way to make them cheaper.
Because we are in a phase of minor tweaks, I have come up with something easy to implement: +100% if you have a source of life mana for Hallowing of the Elohim (which the Elohim don't possess right now, so you would have to research Divination or have to control an world improvement like Tomb of Sucellus to get the bonus) and +100% if you have a source of entropy mana for Elegy of the Sheaim (which the Sheiam also don't possess right now, so you would have to research Necromancy or you would have to control an fitting world improvement - which unfortunately doesn't exist right now).
Because we are in a phase of minor tweaks, I have come up with something easy to implement: +100% if you have a source of life mana for Hallowing of the Elohim (which the Elohim don't possess right now, so you would have to research Divination or have to control an world improvement like Tomb of Sucellus to get the bonus) and +100% if you have a source of entropy mana for Elegy of the Sheaim (which the Sheiam also don't possess right now, so you would have to research Necromancy or you would have to control an fitting world improvement - which unfortunately doesn't exist right now).