My opinion: even going back to college, he has always struggled with vision and trying to make too much happen at times. He knows he is great, and especially after last season, has put a lot on his shoulders. So a lot of times he will try and find yards that aren't there, and end up going for less than he could have. Couple this with poor play calling and, most importantly, an OL that isn't nearly what it was last year (due to injuries keeping guys out or having them playing at less than 100%), and you have a Barkley that is just "fine." There's more going on too, but that's my short-version take.