I don't think anyone has mentioned the ransoms yet.

In MTW after an army routes any enemy troops that are mopped up can be sold for ransom after the battle. In RTW I think it just counts as kills and fractional experience points for the units. You could make some good money in MTW, especially if you caught a king or a sultan.

You also had the choice of buying back troops ransomed by the enemy. If a lot of your good units got captured, if you had the money it was a good idea to buy them back.