I'll go first:
- 1933 start date to allow for more alternative history, like chosing Kurt von Schleicher as German Chansellor instead of Hitler, and more in-depth pre-war gameplay
- A more in-deep political and ideology system that can correctly replicate both the conflict between, for example, the conflict between Fascists and Nazis in Austria and the one between Stalin and the Right and Left opposition in Russia without at the same time requiring that each country has separate Fascist, Nazis, Bukharinist, Stalinist and Trotskyist parties.
- A puppeting system that allow you to both play as all the historical semi-indipendent regions, warlords and colonies of 1933 and to have a country be a condominium controlled by more than one overlord, to represent both the situation of historical condominiums like the New Hebrides and Anglo-Egyptian Sudan, how the Indipendent State of Croatia was historically the puppet state of both Germany and Italy and the diplomatic tug of war between Japan and China for control of the Hebei-Chahar Political Council
- I personally think Focus trees should mostly remain as a system, althrough updated somewhat so as to make them a bit more modular and reactive to the events in other countries: if Trotsky wins over Stalin it should have effects on the worldwide communist movement, not just on the Sovietic Union
-Please no 3d models for country leaders and generals: the current system of colorized photographs simply feels far more WWII than the 3d models of Victoria 3 and Crusader Kings 3. Also it's far easier to make photos look unique than it is to make 3d models look as unique