Here we go. The results of the experiment.
Ways in which the AI is playing by different rules,
or is being treated by monsters differently than the player.
(on Challenging difficulty, in version 1.0)
* The AI can see the map without scouting.
Confidence: High
Reasoning: constant flow of pioneers towards valuable tiles or resources that the AI cannot possibly have scouted, ceasing as soon as the player claims the tile/resources. Observed three times.
* The AIs can settle where the player cannot.
Confidence: Beyond Doubt
Reasoning: Observed.
* The AIs receive bonus essence when they settle a city
Confidence: Beyond Doubt
Reasoning: Observed
* Monsters are less likely to attack an AI army than a player army
Confidence: High
Reasoning: On two separate turns (83 and 104) there were at least one player army and one AI army next to monsters. In one case, it was a stronger player army, and a weaker AI army. In the second case, it was an average player army, one weaker AI army and a stronger AI army.
In the first case, the player army got attacked 6 times out of 6 (7/7 if you count the canon turn)
In the second case, the player army got attacked 5 times out of 7. (8/10 if you count the canon and the two crashes on that turn) The weaker AI army got attacked three times. The stronger AI army never got attacked.
* AI rushes production without paying for it
Confidence: Beyond Doubt
Reasoning: Observed.
* Monsters target player cities more often that AI cities
Confidence: High
Reasoning: Every single time that a monster lair containing an army stronger that a city garrison was disturbed by the player dominion, after 4,5,5,3 turns, the monster headed towards the nearest player city. In the replays, when the city did not get reinforced, the monster attacked in 5 out of 8 cases as soon as it reached the city. In two more cases it attacked a few turns afterwards.
In the replays, I saw at least 7 instances of monsters staying in their lairs 10 or more (up to 30) turns after their lair was covered by the city's influence. In only two cases did monsters destroy AI cities. In one case, the city was built in the path the monster was already traveling.
Note: This was by checking saved turns from the canon play through. As soon as I removed the fog of war, the monsters seemed to become active much earlier. Monsters would also become active if a player unit approached an already disturbed lair (the player unit would be two tiles away, but the lair would have been in AI dominion for a while.) If I were working on this game, I would check into FoG mattering where it should not.
* AIs gang up on the player in war.
Confidence: Low
Reasoning: I was consistently near the top of the pack. No one attacked me. The AIs ganged up on Kraxis as I was crushing it. If the AIs gang up, it's on weaker nations, not on the player specifically. Of course, with all the ways the AI gets an advantage, it's easy for a player to end on the bottom.
* AIs get (at least) research bonuses
Confidence: Average
Reasoning: Altar did too well against me. I had more cities, I was developing them pretty well, prioritizing research, and I had conquered extremely nice conclaves from Resoln, Yithril and later Kraxis. According to the debriefing graph, I had passed Altar's research around turn 100, and never looked back.
Still, if I started a trade, and traded all tech with Altar (both theirs and mine) a few turns later Altar would have twice the tech to trade, even if I would first get all the tech from Guilden and Tarth (paying only resources for it) Altar and I were both researching civilization.
I may be missing something here, which is why my confidence is only average.
* Monsters seem to be seeded around the player but not around the AIs
Confidence: Average
Reasoning: When I reveal the map, I do not see any really dangerous monsters anywhere but around my position. The only dragons and slag are either part of wildlands, or within 12 tiles of my starting position. It may be completely random, though.