@Ondis A lot of Medieval warfare consisted in raiding, especially for the Turks in Anatolia. Assuming that retreating is possibly only the consequence of a fail and that you always and only aim at taking and staying with all your attacking forces in the territory you invaded is ahistorical. Of course, this adds the fact that TripleA doesn't allow you to represent booty, as the triggers giving you PUs for destroyed TUV are very basic, and anyways that is not taking into account the resources of the target territory itself.
nods noted! What do you think of the ability to retreat for both sides? Great kind of moves could be made! The attacker splits his forces in two, the defender attacks one of the stacks, the attacker retreats, the attacker next turn pushes up with the other stack, etc. It could break deadlocks!
This wouldn't work on small maps though where such a retreat gives the defender a serious extra move. But then this could easily be balanced with "if you retreated with your defending forces, you cant move next turn" or something like this. Forcing a kind of perpetual retreat, and pursuit! As was historic. Until you either decide to stand your ground, get enough reinforcements or die.