Build Railroads! Codes! and more.
: Trade Tech and Providences
: Up-grade units. (ex. chose to upgrade light armoured divisions to standard armour so you can keep the division name, experience and leaders. The old armour go into a pool which you can sell to other nations or scrap for say a boost in armoured production for a month or something)
: End the game in 1950 or 1955

eace negotiation that offers to cede territory or demand territory.
: Introduce other strategic resources. Iron, Coal, Copper, Oil. And production and maintenance consume some amount of these resources but less IC. (Say, for example, building a Sherman takes 1 Iron and .5 IC each. and then .25 oil for continuous upkeep. Units in the "pool" require no manpower or oil upkeep.)
: Railroads should be able to be constructed separately from infrastructure requiring IC. Railroads increase supply and reinforcement time to the minimum. They can be built over any percentage of infrastructure but if destroyed (by bombers or partisans) and then needs to be rebuild, not repaired. Sometimes do to lack of railroads supplies and reinforcements get delayed.
: Codes. I saw someone post this idea and I loved it. Codes and intel gathered remain on the map even if it is inaccurate such as enemy airfields, divisions, and naval bases.
: Broken codes. Can see where units that communicate with codes that you have broken. See where the HQ is stationed and the division receiving orders is located. Every time you order units to move the game simulates as if the orders are coming through the HQ. Or you can see the individual unit's current orders along with basic info such as name of division and commander and what HQ it is based under.
: Have a division history in that # killed in battle or # of enemies killed or # of enemy tanks destroyed. To see what division is the most "successful". Maybe also have # of battles won or lost, like a list with battles it participated in with a W or a L next to it and you can click on those battles to see the stats.
: Have planes represented not as individual units but as squadrons of 10 or some # of aircraft. These units are represented by a icon on the map. Same goes with Uboats with floatillas of 5 subs. They would patrol the ocean in the selected ocean territory induvidually and would have a chance based on some % to come to the aid of another sub while attacking a convoy or other ships.
: Have sea convoys represented on the map. Can gain intel on routes to increase intercept and sinkings.