I'm okay with Hershel Walker on the list. But Barry Sanders started only one season while in college. Now that one season is probably the greatest season a running back has ever had, but still should one great season put on the list. As pointed out, I think deference is given to those who had great NFL careers, and that looks like the case with Sanders.
If only one's college career is considered then the list has to begin with Tony Dorsett IMHO.