Well ye, video might prove it all better
But i believe i've been misunderstood a bit on that point.
Unit leader will not be able to control his unit members in any way directly. He acts as a center of certain shape (circle, wedge, rectangle) that is always around him. His unit members are _interested_ in staying in that shape (stay in formation) because they will recieve combat bonuses AND the more unit mebers inside the shape - the bigger bonuses they recieve.
So, in theory, the more organized is that unit - the more members will stay in formation - the more effective in combat they will be agains equal force that is just running around chaotically.