Honestly, there are some things that make me very disappointed. I have high expectations and the reason is because HoI III was my first game and I love alternate history; I expect HoI IV to be even more complex and to have even more choices/flexibility than HoI IV.
Internal Politics:
I wanted an even more complex and better internal politics, which from what I know, it is instead really dumbed down(It has only 3 parties instead of like, 10 that HoI III has and almost no internal interaction). I expected for internal politics to be important and you have some influence, unlike in HoI III where you could only choose from worse to better policies and change ministers.
National focus:
It seems good as a guideline and as goals and as a reward to fulfill those goals but if it limits in any way on what you can do, I hate it. One of the charms of HoI III is that you could do anything you want: You could invade Italy and befriend the USSR, or somehow via coup make US more leaned to fascism, etc.
Diplomacy:
I forgot if there was anything on the matter, but I expect a very expanded diplomacy system. (such as giving provinces to allies, peace conferences, giving troops)
Armies:
The removal of counters. The removal of counters is the strongest of them all, because it gives a special feeling to HoI III and immersion as an general looking over a map. Sprites seems extremely clunky in a game such as this (I can only imagine what a hell it would be to manage Barbarossa) and I'm not too big of a fan on how the armies merge or whatever happens with how armies act on the map. In short, just rework it so it doesn't use sprites.
Map:
The map looks horrible. I know you tried to improve and for it to be universal, but it looks horrible. It's just better to improve the mehanisms of maps from HoI III and just add improved types of the map.
Technology:
It's too simple and it's pretty obvious why that's bad and why it needs to be changed.
Hopefully you guys will see this and improve on these areas I've mentioned because I have faith in Paradox and I can wait another year if I have to if it will improve the game on these areas. These are just my feelings lately toward the game.