I'd say going for the spellcaster is good AI, except the part of running through the DK of course. That's what a human player would do.
No, don't worry, dumber AI does not make a good game either, so I'm not suggesting that. I am just saying that when the AI enemies ought to be blocked (say, like stuck in a hallway, or a door) but they somehow manage to run through the DK, even though the DK shall block them by his big imposing evil spiked black armour of infinite evilness and wickedness.
