Quote Originally Posted by katank
Having an enemy faction leader escape a battle alive is very bad as you will be fighting a full unit of heavy cav just 2 turns later.
It has its upsides, if he ran away he probably picked up a cowardice trait. The morale hit usually makes a battle far easier. Then again, the cowardice traits aren't nearly as crippling as they were in MTW (-9 morale, anyone?)