Listen to Detmer. You have a Jamaal, you obviously give it to him. And it helped make up for other things. It's an "easy" play call. It makes things easier on a new coach, a team in a new system, a supporting cast that struggles. If you take Jamaal out but you fix everything else, I don't see a reason to worry. It's not necessary to have one guy get 250-300 carries. They have plenty capable RBs.
I actually think your comment was backwards. In reality, BYU didn't have a passing game to keep defenses honest. And it was bad. We saw it a few times. So if you fix that, it's going to make things a whole lot easier and open it up for the new RBs. IOW you don't have to have Jamaal for it to work out. If the other side doesn't get fixed, sure, but there's no indication at all that this is going to happen.
Also, using a "well our QB can't get injured" as a reason to worry just doesn't really work. That has nothing to do with the offense and every team in the nation would say hey, we can't lose our star. That's a given. I don't think Clemson fans were sitting around worrying about things by saying man, we can't lose Watson. It's just an obvious factor.