The advantage of a leader is that they can give there order sort of as a reaction.
The general with the defensive order (forget his name). Any place that is attacked within two places of him could instantly have a defensive order. They are not powerful in what they, but in when they do it.
YOU MAY NOT PLACE LEADER ORDERS AT ANY MOMENT OF THE GAME!!! ONLY RECON LEADER HAS THIS ABILITY... STALIN - DURING MOVEMENT. REST - AT ANY MOMENT OF ORDER PLACEMENT ONLY!!!