Benching him is even worse than not. AD isnt taking that team to the playoffs. At best AD makes them competitive in a few games. Go ahead and let Bryce sink or swim in a season that doesnt matter. In fact, I would run a high tempo, heavy pass offense and let Bryce just wing it all over and tell him the outcome doesnt matter. Give him experience, see if he can turn it around and end up with the #1 pick in the process.
Its not like fans are going to be buying tix because of AD starting.