That's a possibility, but what Lee was trying to do took exact timing and cooperation amoungest the entire army. Would the additional troops on the roads made the deployment of his army that much slower coming from the west? I agree, an extention of Lee's right, or a reserve to support the right, would have given the Confederates a much need edge on that part of the field. I don't know if it could have been possible with the additional forces in the column to deploy in time. It is something to think about. Also, the additional units could have supported a second attack during "Pickett's Charge", which had been formed and started to advance when it was cancelled.

David