The various arguments can be easily debunked. First of all, the notion that we have become more intelligent. Only during the meat-eating days of the palaeolithic era, is that true. In the last 35,000-10,000 years our brains decreased in volume by 3 percent(when its theorised we started eating fewer animal foods), and in the last 10,000 years, our brains decreased in volume by a further 8 percent, once the Neolithic diet came in with all its huge amounts of extra grains and starches etc. The decrease in brain-size does not automatically correlate with decreased IQ, but there is a further factor, namely natural selection, which would have been more present in palaeo times, but which disappeared as a factor once settled civilisation came to pass. So, it is reasonably certain that Intelligence dropped when the Neolithic era came about.
The claim re stronger stomach acid than humans in carnivores is, of course, meaningless, as humans have a longer digestive tract/gut/intestine to compensate for that.The notion re humans taking ages to hunt is also ridiculous, as there is the scavenger theory which shows that ancient humans at least did some scavenging of prey after other predator species had had their fill; but also, there are very famous palaeolithic sites, such as at Solutre in France, where it was proven that Cro-Magnon hunters would force entire herds of wild horses over the cliffs etc.:-
http://www.oldstoneage.com/montetwhite/solutre.shtmlhttp://archaeozoo.wordpress.com/2008/04/03/horse-hunting-in-magdalenian-france/As for no evidence about rawpalaeodiets, that's not quite true. There is a HUGE amount of scientific evidence debunking the notion that cooked foods are healthy(such as studies on the heat-created toxins in cooked foods), a number of studies showing negative effects of non-palaeo foods, and most of the studies done on raw vegan diets have shown serious problems arising from them long-term, such as amennorhea etc.
That reminds me, I ought to do a few sticky threads here on evidence from palaeo times, and on rawplaeodiet.com. It's a fascinating subject, given things like cave-art(I often find that those "primitive" Cro-Magnon hunters produced paintings of a far greater complexity and brilliance than anything any modern painter has done since the ghastly Impressionism got started, with one or two exceptions like Escher or Vallejo).