AI Planar Travel

[Seravy]

Deterring the player from war isn't the important part (that would happen as accumulated experience over many games, at best) - not losing that war if it happens, is. It doesn't really matter whether the player loses the game, or accepts peace - and Prayer is the single greatest contributor Life can have for that outcome.
Obviously, Prayer isn't going to stop a Lunatic level strategy from winning - but it is powerful enough to have a chance of turning things around against an average player.

A more important factor is the game isn't fun if the AI isn't putting up a fight, so having something that's a threat is of critical importance. Life has no summons, so that threat is Prayer (and common buffs, but those aren't really that great - dispel is a thing.), unless we want the AI to go for Unicorns first.

Finally don't forget that Altar of Peace is a hit-or-miss spell. The AI might be in wars against its will and might get nothing out of it - even vs other AI. Wasting the first pick on it sounds like a bad move.

Anyway, really time to sleep now. Aside from this, everything else is complete so I'll upload a beta tomorrow for testing.

(one case when picking the Altar over the Prayer is a good choice is if the AI starts on the other plane than the human. However, I think the last thing we want to see is a Myrran wizard that spirals out of control even faster with this, and...actually the Myrran wizard will not have contact with anymore so it'd get crappy research from the spell, too.)

[Seravy]

So, my current thoughts :

Prayer - always pick first, unless starting on a different plane from the human
Life+Nature wizards should go for Stream of Life as it's a good combination with max pop boosting spells
Life+Sorcery should aim for Divine Order as it has the best buffing capacity in the game
Life+Chaos should do Altar
Life+Death should do Altar or Stream
Pure Life should do Altar or Divine Order

...so, I think this is best : 

1. Prayer - Same plane as human
2. Stream of Life - Nature>3
3. Altar of Peace - not Chaotic, at least 4 Chaos books or Charismatic or Peaceful or Lawful
4. Divine Order - Death,Chaos<2
5. Stream of Life
6. Unicorns

[Nelphine]

I don't see how stream matches this spell for life/nature for the AI. Sure they can get high max pop, but pure nature still cap their city populations anyway. 
So i'd switch 2 and 3. Getting Gaia's blessing earlier is far more important to the ai than maxing out the population. And getting very rares earlier is even more important than getting Gaia's blessing.

(Obviously I'd go further and move prayer down one further, so with your current list, I'd go 3, 1, 2, but I'm not overly concerned.)

[Seravy]

The chance of Gaea's Blessing is fairly bad with that few Nature books, and Nature won't benefit from a large research advantage if being Peaceful or Lawful. Sure, they'll get big monsters to summon, but without starting a war, those won't see use. Nature does not have nasty game changing globals the peaceful AI can use to still damage the human without a war, either.
Stream of Life however has great Synergy with Change Terrain and Transmute, which are uncommons. Large early cities with adamantium produce very scary troops (albeit again, peaceful won't use them to attack, but at this time in the game, they can at least clear nodes and stuff for a fairly significant overall economic advantage)

Either way, neither seems particularly impressive (as peaceful kinda negates the AI being a threat in the first place if they play nature) but Stream of Life is more stable, Altar might do nothing if others declare war on the AI. Overall, it doesn't really matter I think, but only time will tell, we need to play against the new spell first.

[Nelphine]

Ehh, getting very rares earlier is ALWAYS the most important thing an AI can do. And with them cutting research during war, this at least gives them SOME research. Still more important. Either they get to very rares, and now they have the godawful combos like behemoth + supreme light, or they have economic superhits like life force + awareness. The human has to go to war before they get to very rares or it's going to turn very very painful - life/nature has the best economy, although life/sorcery is close (life/sorcery has better casting skill), so not going to war isn't really an option. Stability doesn't really matter for AI - they already have stability through cheating bonuses.

But since I don't even like the research bonus existing, I suppose I'm ok with the AI not using it first in some cases.