Great, except for 2 things...
Two things: One, the auto-retreat.
Two, the unit selection.
These two things combined sometimes make winning completely impossible. No matter how many times I tell the stronger force to engage the enemy, it doesn't listen. It picks whichever of my units is closes to the enemy, and forces it to attack. Which in some cases, means that your weak force, which just auto-retreated, is forced into battle again, against the will of the commander. And they just auto-retreat again and again, and you lose.