Why is Adrian Peterson a unanimous #1 pick?

I don't get why Peterson is a unanimous #1 overall pick in standard scoring leagues. He was 9th in total fantasy scoring last year, and behind unanimous #2 selection Michael Turner. Why is Peterson favored so much? Sure Turner hit the 370-carry mark last season, but that was just his first full year of duty. In PPR leagues Maurice Jones-Drew or Matt Forte should be heavily favored over Peterson. I could even make an argument for MJD over Peterson in standard scoring Yahoo! leagues. Pro-rate MJD's carries over 16 games as a starter, and you're looking at at least 1,200 yards/12 TDs rushing, and 650/2 TDs receiving. Add that up and you have 1,850 total yards and 14 TDs (as the feature back 16 TDs is highly achievable). Peterson is highly unlikely to reach those numbers. Figuring in PPR, MJD and Forte get another 60 points that Peterson doesn't, which strengthens my argument against Peterson. I'm not arguing about real play ability here, but rather fantasy points. I would pick Peterson with my first pick if I was starting an NFL team, but not so fast for fantasy.