I didn't read the McDougall article, like everyone else, my response was "who cares". I think that paleo people were able to live well on a range of diets, some were higher in carbs (I can't remember, but there's one group of people that usually gets named as an example here), and others ate almost exclusively meat/fat/animals (i.e. Eskimos). You might also want to check out the Weston Price book on nutrition if you haven't. (The dentist who made a study of many cultures, to see firsthand the effects of different foods).
I think the key that comes up over and over is, eating natural UNPROCESSED foods is best for your health.
Oh, and not sure if you saw this... Mark did write about his experience McDougall-ism at one point, and wrote about it here:
My Escape from Vegan Island | Mark's Daily Apple