I am the least qualified individual to answer ANY question about the AI.
You are one of the most experienced veterans of TripleA. No wonder that such rookies like me need your clever advice.
However, it does not initially address the L&L issue while Japan and Russia are neutral.
In my mod I have cancelled any opportunity for the Pacific lend-lease route by creating "neutral to all" Soviet Far East-faction and have tried to focus the AI on the 2 lend-lease routes:
- long and less-risky lend-lease route through Persia;
- or short and risky lend-lease route through Arkhangelsk;
I thought the Hard AI will chose which route to go concerning current position of German subs on its way.
But unfortunately the Hard AI sends troops only directly. If I were the Hard AI, I personally would choose the Persia lend-lease route even if it takes more game rounds.
The only flaw I see in your approach is that what incentive is there to expand? If you earn what you earn... why invade anything ever?
I place victoryCities on the map for the squares I think historically important for the game to go historical way.
the Germans have spent so much time on Stalingrad.
Before the WW2 the Stalingrad was one of the biggest production centers of the USSR. But after the battle of Stalingrad the entire area, even hundreds kilometers from the city, laid in ruins and ashes.
If I give some important number of PUs to the Stalingrad area, then in the game after Germany eats the Stalingrad area, it will add extra income to the Germany. But it should be no benefit to Germany as the only thing the Germans get are ruins and ashes - no additional manpower and no additional PUs' income.
The Germany is not an amoeba that can "eat => grow => eat => grow => eat ..." Production facilities of conquered areas are completely destroyed, basic infrastructure is destroyed, everywhere there is famine and devastation, population sabotages the invaders, etc.
Also if the Soviets reconquer their land (and the Allies reconquer the Western Europe) they can also not increase their PUs' income and manpower resources due to the same reasons.
So I mod it the following way:
I give Germany the fixed income 600 PUs every round and the manpower resources (the manpower resources are given only once at the start and cannot be supplied any more during the game. So if the faction runs out its initial manpower resources, the game is over like it is historically.)
And each territory receives only 0-5 PUs' value. This difference I need to have the minimum requirement to be able to place different production facilities. For example, the square with the 2 PUs' value allows me to place only small infantry barracks whereas the square with 5 PUs' value allows me to produce heavy tank-destroyers and battleships.
Therefore if the Germany conquers all Europe from London to Moscow, the Germany will be able to place the production facilities on all these squares according to the PUs' values of the correspondent territories. But the total production output will still not be more than fixed 600 PUs (the Germany gets every round) + small number of PUs from the conquered territories - PUs spent on upkeep - PUs spent on fuel (in my mod Japan and Germany are charged PUs every movement in order to represent their oil shortage of WW2).
but being worth nothing?!? Seems counter intuitive to the philosophy of taking foreign territories in the first place.
Colonies are worth occupation and exploitation, major powers are not. Major industrial powers are worth stopped and defeated but not occupied.
Im my current mod I add to the fixed German income the income of Germany, Austria, Czechoslovakia, Scandinavia and some eastern European minor countries (based on their GDP values). But not the income of France.
Why? Because French contribution to the Germany during WW2 was only nominal. Maybe 1% of what France could have given to Germany or even less. "De Gaulle saved French honor and Petain saved French purses."
Also I do not boost the PUs' fixed income of any other factions if they conquer or reconquer any territories.
If any faction is losing territories I also do not change the fixed income the faction receives every turn. Because with the reduced number of territories the remaining production facilities get more limited. And the fixed income helps the losing faction to start production of small numbers of high-tier units. And therefore to boost the resistance of the losing faction.
For example, if Germany expands it focuses on huge numbers of cheap infantry and PzIV-tanks whereas if Germany has only Berlin left it focuses on Jagdtigers and 128mm-Pak44 guns with huge defensive stats.
Also I should say I don't like Axis and Allies to be equalized like in the most TripleA games. Historically Allies have been multiple times superior to Axis in all terms (GDP, manpower, oil).
I try to use historical GDP and manpower ratios and additionally charge Germany and Japan with fuel costs.
And it makes me so much fun to play for Axis and to be under steady growing pressure.