It could be fun if it was possible, when the general was attacking, to press a button or something, so you get the same view as when you replay the battle from the mail. You can then see how the battle progresses, and if it goes bad compared to what you thought you could press a "RETREAT" button. Since it wouldn't be free to escape the battle field, you would naturally lose 10 -> 50 % of the remaining men, depending on the composition of your army. (if you have longbows or cannons, they would be able to cover the retreat, and you would loose fewer men, if it is only recruits, you would loose more, since they are more inexperienced and weeker). This way you don't have to loose all your men.

-KarstenL