Maybe I should have elaborated on why i think Germany is a learning experience.
1. If you are playing this game, I assume you know the basic chronology of events leading up to WW2 most of which include Germany.
The goal of this game is to bring in more of a mass market, which includes many players whose knowledge of WW2 is from the media and what they retain from school, which judging from surveys may be relatively little. Knowing the chronology is a spoiler anyway - something readily manageable but active enough to be interesting is the goal.
2. The nations you fight as Germany increase in difficulty over time ranging from very easy(Poland) to quite hard(UK and Soviet)
True, there is a progression, but there are also opportunities to make lots of serious mistakes in direction, emphasis, and timing. Plus managing war on multiple fronts is more complicated, thought hte battle planner seems like a dream come true.
3. You have the ability to research everything usually
And you should pay necessary attention to all areas, bearing in mind trade-offs. This is a compelling point for some, but others may want to stick with land-based warfare for their first game.
4. You have a high industry cap that can increase by conquest.
Bigger can be better.
5. You have many potential allies
And enemies, and in fact a range of multi-faceted alternative grand strategies and operational strategies that permits a wealth of unforced errors. Lesser powers can offfer more clarity in grand strategy and operational alternatives.
6. You decide when the war starts if you play it not overly aggressively.
Don' know enough about whether there is railroading of events that would preclude a power or a Balkan minor starting up something in their own interest that polarizes the continent into warring blocs.
7. You get country flags (which i guess are national spirits now) for your troops in the first few years of ww2 that make them even stronger on the attack.
Indeed, "Blitzkrieg" was sexy from the moment it was invented. As WWWednesday shows, you can also conquer with good old boring infantry divisions.
All of these allow many mistakes as Germany while learning about expansion, research, invasions etc. Its one of the nations that have a good pace from the beginning and gradually increase over time, unlike a lot of countries which do very little, or suddenly gets thrown in ww2 with no much to work with.
Germany is likely to make mistakes and resilience as well as the advantage of interior lines with excellent transport infrastructure helps mitigate them.
The UK, however, is not a beginner's choice, as its position is extensive and understaffed with troops; one might call it Imperial overextension. It has many opportunities to make serious mistakes and a rose position to respond quickly to recover.
I am very much against learning the game playing as an insignificant nation because you'll teach yourself tactics that won't work against serious enemies, in order to learn the game you have to fight enemies who are actually dangerous, you'll learn a lot more from winning against UK and the Soviet Union as Germany, than you will beating Uruguay as Paraguay
Agreed, though restoring Uruguay to a revived Empire of Brazil and conquering South America should be an experience, particularly in strategic forethought and logistics.
Of the great powers, I think Italy is a good choice for the reasons stated because the mechanics in HOI4 appear to make it much easier to manage logistics, troop movements, invasions, and air and naval assets and it can operate under a coherent plan for its Med-centric theatre of operatoins.
Minors such as Romania or Hungary don't have a need for naval forces and will get to do some heavy combat in their own interest, fighting with each other over Transylvania if not elsewhere. China would be an infantry war on a large scale. Spain or Australia have naval as well as land forces, and can make their mark on the war - Australia in Africa as well as Asia. And there is always Sweden - whose secret aspirations for pan-Scandinavian empire and nuclear domination are revealed to the world for the first time in this game.