Good explanation Fog, I was going to answer by saying sometimes the fight leading the Warband isn't just about killing destro but also about keeping the people following your banner. As people are fickle the hardest part is getting the right number of people following and listening to make the opportunity available to find fight and defeat destro on the appropriate battleground.
'A clever general, therefore, avoids an army when its spirit is keen, but attacks it when it is sluggish and inclined to return. This is the art of studying moods.'--Sun Tzu
If you have made everyone happy with success in small victories they are more likely to follow you through large battles and sometimes even stick through a defeat.
When outnumbered, demoralizing the opposing force to cause attrition via DC/idleness is an effective method instead of fighting with an uncertain [in skill/trust] force against a larger zerg, as the smaller force needs a observant force willing to trust the leader to call out commands and take down the key targets to win. Without the trust the zerg can roll causing a CRAZY morale hit on friendly forces, which then makes a win more difficult as your small force just got smaller. A self-defeating cycle.
'Reduce the hostile chiefs by inflicting damage on them; and make trouble for them, and keep them constantly engaged; hold out specious allurements, and make them rush to any given point.' --Sun Tzu
Capture enough different locations then you split the zerg into manageable chunks and end up with a easier fight on your hands. Another success that increases the willingness of others to follow you to even more victories. Greater danger with an ear for order and a greater chance for victory. Splitting the enemy is the surest way to ensure success and when the battle is joined the true purpose is to win.
'Numerical weakness comes from having to prepare against possible attacks; numerical strength, from compelling our adversary to make these preparations against us.' --Sun Tzu
...Ludo.