Which spells the AI will never cast?

[K]

That's a great topic.

Everything is dependent on what you research. This means that to get a smart AI, you often have to NOT research a Path.

For example, let's say you are facing low HP, unarmored or lightly armored stuff; Fire Cloud is awesome for that, and since it last 3 rounds you can kill a lot of chaff with a low expenditure of fatigue.

But, let's say you have Falling Fires. The AI loves Falling Fires and once your script runs out Falling Fires is cast instead of Fire Cloud.

So if you want a fire mage to not cast Falling Fires, you have not research Falling Fires.

On a lighter note, always research an S1 AoE buff like Body Ethereal before you get Blink. Otherwise, your S1 mages will cast Blink and effectively commit suicide.