Okay, here is my take.
When Wegher was being recruited and everyone saw his weight lifting video, there was some concern as to how much room for physical growth he had left. This seems to be somewhat confirmed with the coaches asking him to lose weight.
Watching him last year, his big attributes were leaping over the pile, receiving, and running in space. He did not show much ability in running through tackles or moving the pile. Hence his high total of negative or very short yardage plays. Just didn't look like he had the body to be a Big Ten workhorse. Again, hearing the coaches actually wanted him to lose weight seems to lend some credence to this. Losing weight just doesn't seem to be the road to carrying the load at RB at Iowa.
However, at USD this kid can have a shot at having some huge games. While at Iowa he would be one of the better athletes on the team with a specific skill set, at USD he has the chance to relive the dominance of his high school days.
I mean he has his BCS game highlight tape. That is proof that he can play on the biggest stage. Nobody can take that away from him. If he would enjoy his life more by dropping down a level and dominating, so be it.
I mean who knows? Such a move has worked out for some guys really well.