Reinforcements would be interesting. I had thought about allowing you to spend experience points to purchase reinforcements instead of adding skills. For example two units with 3 xp each, and instead of leveling them you spend those 6 points buying 'x' # of points of reserves. Let me think about it, and I welcome any input on how to best go about it, but as far as that goes I think that it should be done at the end of the turn.