He opened up as a receiver, but his really good rushing games only game against the awful opponents.

Consider that Jamaal has never played a full season. He didn't get to start as a freshman for the first few games. Then last year he had almost 6 ypc behind a historically bad OL for 1200+ despite missing the equivalent of about 2.5 games.
Jamaal's pass catching abilities aren't non existent. He had 300 yds as a freshman. They just don't pass to the RBs much anymore. That was a staple of the offense for Beck and Harline. I don't think you have to go on total stats alone to make a judgment call on better performances. When it's all said and done, it won't even be close.