how so ?
Gibbon goetia gives you lvl 3 spells way before your "friends" have mage. and maybe before your friends have priests. (SP or MP)
for the rest
divine 3 ?? WTH ? that's no religion tier 4 !! well , it is.. but almost no interest !
I'd rather have druids upgraded from the adequat priest to get that wonder tier 4 spell ! you don't have to stockpile an insane amount of xp, that you lose the next time you switch religion and that is somehow weak : how do you subvert strong units with a 8

unit ? (some of my prefered are confessor upgraded druid ! -for the 80% command or stonewarden-updraded druid for the earthquake. but you only need one of those.) .
but on the whole I agree with you. shadowriders and gibbon goetia are not sufficient to forget Yvain or Sphener or sacrifice the weak, or tsunami, ring of fire...Etc + cure disease)
so maybe the issue about COE is mostly that so much of the COE boni are available without having the state religion (invisible units with the holy city, shadow, mask, participation in the undercouncil -buying nightwatchs, and what is limited to the state religion is not so powerful or comes too late)
Maybe it would be better if any "COE" recon unit gets another -useful- spell when the state religion is esus.
and maybe that not only svart can get
steal , but any shadow of with esus as state religion.