EDGE has a feature up here: http://rampancy.net/weblink/bungie/Edge_Interviews_Isla about the AI in the Halo series. They interview AI programmer Damian Isla, where he brings up an interesting concept I'd love to see in a Halo game-- or any Bungie game, really:

There was the well-known example in Halo 2 where your 'hog full of marines would just drive off if you got out. That's actually not that easy a problem to solve because how does the game know you intend to come back?

My grand thesis is, what if you can say: "Wait for me"? Communication with AI has been sorely neglected; you can ask them to charge, retreat, go there, but what about a richer level of communication than just orders? Even just a 'You're doing it wrong' button - literally.

Yes, Damian. Please. Yes.