General:

1.Rework the fuel system where it isn't extremely difficult to gain fuel. I suggest implementing a temporary national spirit that limits fuel gain for a short while(More forgiving to players and realistic. Even if a civil war did break out in America you aren't going to see a complete stop to civilian consumption/production, granted you will have shortages at first because everyone bum rushs the stores to buy 6 months supply of food/water/fuel(Could be turned into a feature))

Perhaps implement a feature to "Start Fracking" for oil.(Player spends X amount of political power and will temporarily gain a national spirit that boosts fuel production at the expense of stability or political power)

2. Give players the ability of when to choose their wars/battles. I dislike the feature where your nation automatically declares war on another nation as soon as X condition is met. Having this would also make it easier for AI to win wars instead of it being a predictable outcome every single time.

Nations:
Autowaffen- Add new focuses that add civilian factories and more importantly resources(This can also be realistic). Even out in the desert, there are loads of abandoned mines that still house precious metals. Not enough for large scale industrial applications(i.e. providing all the copper for wiring a dozen city blocks) but enough for a communities practical use(+2 steel or something). This could be balanced out by adding a national spirit "pre-industrialized wasteland" that limits production efficiency,etc.

Add a raiding mechanic where you can raid other nations to capture war prisoners and equipment(+[X] amount infantry equipment, +[X] amount manpower)

Indian Nations- Pls buff, give them focuses to add more equipment/manpower("Rally the warriors!" or something. Make them a interesting opponent to defeat.

Mormon Nation: Pls add more resources(Steel, Aluminum, etc) or the ability to acquire these resources. Pls look to previous post on autowaffen for ideas to build up resources.

Molossia: Interesting features and mechanics at play here, but doesn't matter as you immediately get boned by the mormons. Perhaps buff them a bit just to survive or add a mechanic where they relocate when they lose(just like in old world blues mod)