I would like to see the following:
1) An AI controlled Air Force that doesn't sit on the ground while enemy bombers fly overhead.
2) Statistics that show actual manpower losses and POWs instead of IC.
3) AI controlled Armys that actually utilise any attached Air units, I always attach some CAS, Multirole, TAC and Interceptors to my Armys so they can push the front harder, while also having a separate Air Force for air supremacy and strategic bombing.
4) AI controlled Armys/Corps that doesn't split off a random division to send to the far side of the Theatre despite having orders to do otherwise. If I make the mistake of not defending a region, that should be my mistake.
5) AI controlled Army/Corps that despite being in 'prepare' mode for a while, then switching to blitzkrieg or attacking, doesn't instantly retreat when I declare war. Why would you do this!?!?
6) The ability to save an entire Army makeup into the build system, instead of just divisions, I'd like to train, build and deploy an entire Army (or at least a Corps) without the tedium of attaching Divisions to Corps, Corps to Armys....
7)
Please don't take away our ability to modify text files so that we can play the game the way we want to. I give everyone a massive research boost so we can all fight with late war tech, while also preventing the use of Nukes and Jets, because that's just boring. Also I like to cheat while learning the game, but reducing my cheating as I get better (mostly I boost the enemy), normally after a few million casualties...
I literally won't buy the game if anti-cheating goes in. (I don't care about multiplayer anticheat as I play offline)
8) Decoy attacks, If HOI4 can steal your battle plans, then I'd want a decoy Army to enact a decoy offensive then break off. Purely to make the AI think that one of my plans they've stolen is the real one. This could be for instance a massive artillery attack but no offensive, or building fake tanks and aircraft.
9) Timed attacks, say Division A) waits until Division B) has reached it's objective or some other condition is met.
10) Not going to happen but major bridges should have their own place on the map embedded in regions, we can't re-do Market Garden without airborne assaults around bridges. Capturing of a significant bridge could mean not having to wait for a makeshift bridge to be built and greater supply throughput.