I agree that, insofar as people have something like utility functions, those are probably bounded. But I don't think that an AI's utility function should have the same properties as my utility function, or for that matter the same properties as the utility function of any human. I wouldn't want the AI to discount the well-being of me or my close ones simply because a billion other people are already doing pretty well.

Though ironically given my answer to your first point, I'm somewhat unconcerned by your second point, because humans probably don't have coherent preferences either, and still seem to do fine. My hunch is that rather than trying to make your preferences perfectly coherent, one is better off making a system for detecting sets of circular trades and similar exploits as they happen, and then making local adjustments to fix that particular inconsistency.