Atwork
Immortal
It's clear that the AI is programmed to defeat the human player at all costs. It only seems logical that they'd all be in it together
I would support such behavior IF the AI civs actually did coordinate strategically to accomplish self-interested goals. In other words, if both AI-A and AI-B have interests, or even mutual interests, that are achievable only by coordinated activity, or would best be furthered by coordinated activity, then by all means, they should act in concert. An opportunistic AI that coordinates strategically with others advantageously is a welcomed change.
However, AI-A should not cooperate with AI-B in a coordinated attack against the human unless (1) AI-A has a significant chance of gaining something as a result & (2) the goal is achievable.
If AI-A stands to gain nothing, or worse yet stands only to lose, significantly, then the AI programming should lead to AI-A avoid coordinating with AI-B in an open attack. Perhaps there is another way that AI-A can advance its interests by working with AI-B, but in a way that won't lead to AI-A's demise. Examples: financial support, gifting military, open borders, resources, helping AI-B diplomatically by denouncing AI-B's denouncers, etc.
In the end analysis, the programming simply should not push AI-A to coordinate with AI-B if AI-A stands only to lose and therefore be weakened relative to the human and all other civs. On the other hand, if coordinated activity is advantageous to AI-A, then AI-A should coordinate its activity with AI-B.
Now, in my game's case, there was no issue of coordination. The Aztecs did not coordinate its activity, but rather isolated itself from everyone (including its sponsor state -- me) and therefore stood no chance of winning, instead guaranteeing its failure. That's horrible programming!
The Aztecs would have had more to gain by coordinating its activity with me against the 3rd-party civ that it was already at war with. I would have been willing had the Aztecs asked. Instead, they DOWed me and ended up surrounded. After losing nearly its entire army, another civ declared war on the Aztecs. Aztecs begged for peace with me -- I accepted and then ended up funneling them a military so they could survive.
Sorry the post is so long!!