Although I don't play them often, I get a kick out of alt history dlcs like sunset invasion, and the hoi2 dlc that recreated the world into equal countries.
They'll probably continue adding features like espionage, probably with certain dlcs catered to different countries, similar to how they do dlcs for Europa and ck2, like horse Lords for the hordes, Cossacks for Russia, etc.
I could see a Korean war dlc, but as I've said before, a war confined to a small peninsula wouldn't be very exciting since you'd basically have all your soldiers in 1 or 2 provinces. Also, it wouldn't be a realistic extension to the game, since you'd have to have a generally historical finish to ww2 to have a Korean war be relevant, and would therefore have to be played in a separate start date that takes place after ww2.
I'd enjoy it if they made it less focused on a historical Korean war, and more focused on extending the true game date, such as adding techs that go beyond 45, maybe national focuses with qualifiers *must have been a victor in a world war.
Also, instead of focusing on the actual Korean war, focusing on an espionage system that basically makes ideologies target other countries more in depth than just influencing and staging coups, so that Korean war type situations arise when a faction leader tries to take over a country by, let's say, empowering the Communist party, and they add a feature that lets the other party of the country, let's say the Democratic party, request help from other democracies.
That's my number one request, more party decisions and features. It would also be cool to BE ABLE TO START A GAME AS A PARTY THAT IS NOT IN POWER IN IT'S COUNTRY AT THE START OF THE GAME, and trying to gain power for your party by requesting help from countries with similar ideologies, eventually taking over the country. It would make much more interesting scenarios, since you could basically change your countries politics more easily, especially for countries that resist change.
That'd be freaking amazing.