1) Cultural Differences. It seems broken in the game as every capital HAS these differences. It makes it a bit of a hassle to maintain the glorious absolute monarchy when you have -6 to cultural differences, and it seems to be a common problem everywhere. Like, all of Europe was displaced and reconquered by impostors. If it could be fixed, that would be great, but if it isn't, then could it be removed?
2) Building Trees. This is a more difficult issue as there are more than the usual buildings, more branches, etc. Far more expansive. However, there is a bit of a problem with the military building and the administration building. As both can produce regular Rifle Infantry, the Military Building providing a heavily upgraded at the very end of the line and the Admin Building provided a single upgrade... thing is, whichever building tree is completed last provides the Rifle Infantry. That means that something that doesn't take long at all to make would have to wait until the Admin building is utterly complete. In addition, I learned that you can't even destroy and rebuild as the military building doesn't exist. If you destroy it, its GONE forever. That hurts my feelings. And some of the buildings in the surrounding towns tend to... well, be something else. For example, I discovered a vineyard was remade into a logistics base or something. And some of the universities can't actually research when built from the ground up, I saw (or was rebuilt from something else, can't remember, but still an issue.)
3) Navy Battles. They are like regular navy battles, but far more hectic. They're faster, more violent, and very expensive when compared to vanilla. And the expense is my greatest issue, but maybe I'm just cheap. That being said, I don't feel there was a great enough focus on the battles. I'd also love to see submarines and u-boats, give them a bonus when attacking trade routes or something. Most countries have marines, why not place the character models on the ship as well? Maybe add machine guns to the deck. Make it more modern, give it a bit more immersion.
4) Siege Battles. There are no walls... yet you can't take it unless you have artillery. What? How does this work? It doesn't, but I think a good way to get by this would be to grant grappling hooks to all infantry to simply override this effect (this is probably due to airports taking the place of the wall, thus any airport requires artillery for a besieging army to take).
5) Autonomy. This... is actually an observation, I noticed Eastern Prussia (maybe western) still had it despite the patch saying it was taken out. Just letting you know.
6) Light Machine Guns. They are considered artillery. I can DEFINITELY see regular machine guns as artillery... but light machine guns should be regular infantry, just like the SMG Infantry. It would be a lot more interesting, less guys than SMG infantry but a bit more range than them or something, and it would make the Chauchat (which was crap, mind you) more realistic. Personally, I would LOVE to see Americans with the BAR. Speaking of Americans...
7) Americans. I actually enjoy the fact that Americans are a part of the game... but I was surprised how they're implemented in campaign. If you don't know, you liberate the Netherlands. Liberate. Friggin... liberate. That explains why the Americans are orange when you play the instead of a nice American blue. But... removing the Dutch? If you are trying to play a Historically Accurate Campaign, you have to declare war on the Netherlands in 1917, and even then you have to wait a bit. It would be awesome if it were a scripted event where America is granted Normandie or something and joins the war in France's favor, whatever that may be. Or something, just anything than that. And with THAT being said...
8) Liberation. I make it more of a game to liberate nations, and I notice a lot of interesting things, ie Americans being Dutch suddenly. Pretty nifty, I'll admit... Though I was very surprised to see that when I pushed into Italy... I had the option of liberating Serbia. What? Why not the Balkans? Well, whatever, I will just push into Austria-Hungary and take Croatia. Still not with Croatia? Well, lets try the Balkans. Still not? Only Italy? Well, that bites! Look! Ukraine is a country, but I don't like how Odessa is the capital, let me liberate Kiev... Still no? Hardly Ukraine. I can't liberate France or Italy, so once they're dead, they're dead. Why not maintain Italy as Italy and move Serbia to Ukraine if you need a place for Serbia to be based so they may be liberated. I know France can be a bit difficult to make liberate-able, but it could very well be worth it.
9) The Army Pieces. They look atrocious, couldn't you ninja a character model from one of the armies? Use a model with a Kepi for regular army and a helmet for one with a general.
10) The Ottoman Pieces. Including naval pieces, primarily because of the same reason as 9).
11) Tanks. When I saw there were going to be tanks, I was expecting four tanks in a unit when played on maxed unit size and one when played on the lowest. I was very surprised to see it was simply individual tanks, no matter the size, just a different sized tank crew, all with knives and all invisible. Though impressive, I was expecting much more.
12) Knives. They're fun, they're amusing... but all the officers have them. The GENERAL has one. Again, I was thinking the general and officers would have swords or something, so I was pretty amused when I saw them treat the knives just like swords, with such grace... Well, maybe not, but I would very much like to see the general with a sword.
13) The Generals in General. I miss the ability to rally and all that fun stuff.
14) The Campaign Prelude Text. You know, that intro that was written in the beginning that gives you a bit of insight that is happening at the time. It was interesting, but had a few grammatical errors and spelling mistakes and could do with a revision.
15) Governments of Countries. Switzerland should be a republic, the US when liberated should be a republic, the Netherlands prior should be a Constitutional Monarchy... and I have to say, I wouldn't mind if you used different flags amongst the different government types. For example, if Spain had a Constitutional Monarchy rather than Absolute, they use the Fascist flag. It'd be very interesting, though a bit strained historically.
16) Agents. Researchers apparently fly planes... and when dueling, dueling with a gun is maneuvering and dueling with a sword is a gun fight. Nitpicking here, but it does bother me more than it should. As Spain, I began with a spy who was like... 90. It was crazy, but he was pretty awesome at what he did. Bombers... well, I kinda wish that the bombers had the same ability as the Guerrillero from the Spanish Peninsular Campaign, where when they sabotage an army, they also inflict attrition damage. Considering bombers bomb an army, it would make some sense if it actually does damage.
17) Artillery and Emplacements. I may be too mobile to notice, you probably have done this, but I was expecting emplacements for artillery, too. Also, maybe land mines as one of the emplacements. But, again, maybe there is a lot that is done as I am very mobile in the campaign