Well, nobody has mentioned this yet, but targeting by units like spiders is still a problem. Spiders routinely web a unit that has already been webbed, or beguile a unit that has already been beguiled. The AI choice of targets has definitely been improved overall (not choosing ranged units as much, etc.), but I think the AI is processing its moves so far in advance it fails to check to see if the unit is already affected by the effect in question.
