Some things I’d like to see:
1. Terrain effects on movement and combat. Maybe print a movement cost on each territory, to represent: 1.) the difficulty of movement through mountains, jungles, forests, or undeveloped areas with few roads; 2.) the difficulty of keeping units supplied in rough terrain; and 3.) the vastness of the area represented by some territories. If the Japanese really want to send their tank armies to Moscow, or the Italians want to drive overland to South Africa, it should take a while.
2. Rail movement. Allow each country to send 2-4 land units per turn by rail, which gives them unlimited movement, as long as all territories through which they pass were freindly controlled at the beginning of that country’s turn, and all are connected by land. Each country would have its own rail allowance. For instance:
Russia: 3 units
Germany: 4 units
Italy: 2 units
USA: 3 units
Britain: 3 units
Japan: 2 units
ANZAC: 2 units
China: 1 unit
3.) More realistic starting forces. This would involve a larger set of playing pieces. But the more units on the map, the lower the likelihood of one or two bad die rolls deciding the game. The more dice you roll, the closer the results will be to their statistical probability. The Royal Navy should not be wiped out by 3 subs and 5-6 aircraft.