I know this is an old topic, but I gotta say, the defenses Ball played against aren't as good IMHO as the one's Richardson had to face. There is not much of a comparison when you look at the big 10 vs the SEC. Just look at the NFL draft and who goes when. SEC defenses are head and shoulders above most other conf's in defense.
Bama will have another crop of great RB's this coming season (2013) Justin Fowler, T.J. Yeldon and Derrick Henry (all time leading rusher nationally in high school). Yeldon had a great season in Bama's run at another NC as a true freshman. Fowler was injured early on and had his knee done, but was almost ok to play against Notre Dame in the title game. If Henry can learn the plays, Saban has shown he isn't shy about putting a true freshman in there. Bama has a couple of other RB's who saw limited play who could factor in.