1). AI that doesn't make moves that are going to easily put it out of supply.
2). No terrain hit absorbtion for armoured units.
3). Attack/defence penalty for armoured units in cities and heavy woods.
NOTE on points 2 and 3: Armour is not well suited to combat in dense woods or urban environments, the game should reflect this.
4). In the battle screen, have a bomb graphic/sound effect for Germans when they have artillary support and an airplane graphic/sound effect for Allies when they have air support.
5). Ambient sound effects based on weather conditions. Stormy or calm (no storm sound).
6). A slightly darker shade to the map when the weather is stormy.
7. When Allied infantry units are making a 3 space move, have their graphic change to a truck with 'truck' sounds.

Option of adding a unit to a space where a battle is already going on, and not having to conduct combat (on their own against the entire enemy force).
9). Have a chance that the weather clears a day sooner or a day later than usual.
10) Option of playing out game to the end with variable levels of victory/defeat. eg. Total victory, tactical victory, draw, tactical defeat, total defeat.
I've really enjoyed playing this game, fantastic job. I look forward to more in the series.
Mylo