As it is, combat still has no random element once a battle has begun. This doesn't simulate warfare very well at all, and it needs to be fixed. Warfare is not the focus of CKII, but it should not be neglected as it is still quite important. If this were incorporated, the political situations that emerge would not be as repetitious, and the game would be far more interesting and unpredictable. The character who has the most levies as of now is pretty sure to win any encounter. My proposition is not to ruin the system by making the random element the decisive role, but rather to make outcomes be forged on probability.
What I suggest is for each flank to have it's own die (this could be displayed in the corner of each flank's icon). All other modifiers and mechanics would remain the same, but for each flank in a battle there would be a die with a range of -3 to +3, which would give a corresponding advantage (or disadvantage), to combat with 10x the number rolled in a percentage. For instance, a dice roll of -3 to a flank, would give that flank a -30% modifier to all combat done by that flank. Yet, a +1 would grant a 10% modifier to all combat done by the flank that rolled the die. In this way, there would be a maximum of 6 dice for any given battle. Similarly to EU3, the dice would be re-rolled every 5 days.
What are your thoughts concerning this?