Been a long time coming. I'm quite excited for the ahistorical mode, the historical mode still does railroading even though it's not perfect (and I'm sure it'll be refined post-release), but previous games were not perfect either with the railroading. From my observations over time, at times it's really accurate and times it's not, I'm sure it'll be simulated better with our feedback. I'm also happy that there is also the ahistorical for what-ifs, it seems like a clear design path Paradox has been going for, the EU series took the same path with IV. HoI 3 was a good game but it also had a few broken gameplay systems that were never fixed, maybe HoI 4 has found it's footing with overall design changes they've made with HoI 4 outside of the simulation itself, we'll have to see.
Also I am German but not currently living in Germany and my Steam's store is changed since my residence also changed so I am able to buy the "full" version and according to their FAQ when I return back to Germany I will retain it.
Can't really comment on the new iteration of the series but previous HoI games are notorious for their difficulty, they considered the most difficult out of all their games. In any case this is from various reasons, for example in Hearts of Iron 3 the UI is atrocious in many areas and a lot of thing are obscure, there's also a ton of crazy micro with a lot of details that were verbose which made it artificially difficult outside strategy itself. Nonetheless the strategy tends to be very difficult from their other games, HoI is a war game, you are heavily focused on building the actual army itself such as its composition, theatres, the divisions, brigades, the front lines, supply lines, planning, etc, which requires knowledge of military command structures. That sort of strategy still exists in HoI 4, but thankfully they have refined the way you actually do these things (i.e they stepped away from the utter micro hell on a whole new level that was HoI 3), the UI for it for example is much better so it's removed a lot of the artificial difficulty. Tey did make an effort for it to be easier to get into from what I've heard of those that have got to play it (and from their own dev diaries). It's important to remember that the gameplay is also about building an actual army - not as simple as just constructing units and moving them to parts of the map. There is a lot of mechanics involved with creating an actual army, supplying it, as well as war strategy such as front line planning.
