You even bolded my sentence when I said "...when healthy". AA isn't healthy and he can't run the read-option effectively right now. Heck, ARob isn't healthy right now. AA and ARob were not healthy at times last year. When healthly ARob can rip off some yards, he still had a 1200+ yd season last year and AA ran for 500+ and I believe led QBs in rushing in the B12 last year.
Arnaud isn't good at running the read-option...healthy or not! He got most of his yards last year on scrambles. I don't really blame him because as far as I know he didn't run that in high school. It is something you need to practice over and over.
ARob is not the same back as last year. There is a huge difference between the way Johnson and Woody hit the holes compared to Robinson.