Also incredibly grateful the game is still getting attention!
Just another idea since you mentioned you'd be looking at morale and gameplay. There's a really great Darkest Hour mod called Nick's multiplayer mod. It tries to tune the wacky DH combat results with a very simple change.
When units move, they either outright lose org or at least don't gain it. The only way to increase org is to sit in one place until it goes back up. Attacking costs org and often moving does too and units obviously retreat when they run out of org.
This simple change means that lightning campaigns become impossible in places with poor infra (because it takes longer to get there = more org burned) even if you have faster units like MOT. It also makes the regular campaigns (like in Poland or France) feel more historical too.
I mean, for the record, this is how it was done in the original HoI2, and one of the changes AoD specifically introduced was to reverse this. DH combat results are wacky because it doesn't have stacking penalty, unlike AoD, not because units regain org while moving.
In my HoI2 experience, this feature was more annoying than anything else, since it would lead to an endless back-and-forth in infra-poor areas since units would run out of org entirely once they arrived there, only to be pushed by instantly by an attack from a nearby province.