I haven't seen Justin do the things that a great QB does.
He doesn't seem to hit receivers in stride, or lead them to their open side.
He doesn't seem to 'thread the needle' with passes close to the ground or to the out of bounds line.
He isn't calling the quick counts when the defense is in a poor formation.
We seem to ignore this because he's a great athlete.
He can run, but the great QBs don't rely on their running very much.
If he keeps running, he will get hurt, similar to the end of this season.