Someone suggested something these lines awhile back, although maybe they used map commands to do it. Anyways, what I've done is manually create gods for all the AI nations. I try to pick either immobile gods or those with recuperation (and I give the recup ones no or little magic). Sometimes I do immortal but I'm not sure the AI is smart about keeping an immortal god inside their dominion. Basically a pretender that can't easily get itself killed or one that can die over and over with less penalty, since the AI is going to do that
Anyways with the low cost pretenders I give them great scales (high growth!) and a good admin castle (usually fortified city) since the AI won't build another.
I play the first few rounds to get them a good prophet and starting troops, then let them go. Even without the bonus points, the AI does well enough to be a challenge. It is not perfect -- you know where everyone is and what capabilities their pretender has. But I've found them to be enjoyable.