Indeed, it's almost unthinkable that Soviets won't be coming next. I also have a suspicion that they'll squeeze in Italy too. There's no real need for Italy to have its own dedicated expansion because all of Italy's neighbors of note already have focus trees. I think there would be a riot around here if both Soviets AND Italy didn't get one simultaneously in the next DLC..
With that said, I personally wouldn't mind Italy being put off to later if it meant getting a Soviet rework, plus polish rework, plus all of Scandinavia.. that is perhaps a bit too ambitious.
I'm more interested in new mechanical improvements. Logistics, yes, yes, yes, yes. Absolutely needed. It's extremely frustrating to see the AI incapable of respecting supply and it killing off all your supply and preventing attrition. But simultaneously, new logistics mechanics could also be fun and engaging, and good for balance.
In multiplayer games, we have noticed a definite trend: either the Soviets more or less stop the German offensive at the river line that goes along Riga to Kiev, or they lose the game entirely. The obverse is also true, if the Germans fail to get beyond that river line in 1941, then they more or less automatically lose. The game's mechanics actually don't currently allow for a situation where the Soviets take huge losses and huge territorial losses in 1941 and yet allows them to rebound. New logistics mechanics which actually make it more difficult for the Axis to reach deeper into Russia would potentially be a great improvement.
This would also be a good time to do some reworks to the way plans work so that it is no longer micro hell to get planning bonus, changes to width system(1 division with 20 battalions of infantry magically being stronger than 2 with 10 each, etc). A warfare rework in this vein would also allow the opportunity to revisit doctrines and make them more distinct and interesting. A rework of plans/planning bonus could also make GBP a viable choice for a change. GBP has a few stubborn defenders, but I'd go as far as as to say there is a general consensus in the community that it is really bad and never worth taking outside extreme niches. This largely relates to the difficulting of gaining and maintaining planning bonus.
Planning bonus is really easy to make use of for large groups of infantry, but they're also the type of division that will actually gain the least from it, since no division type is less suited to attack than infantry. When I use armor, even if I may have 12-16 armor divisions, they are separated into groups of 4(if 20width) or 2(if 40 width) and distributed along the front so they can work in concern making pockets. It's too micro intensive to make individual, one province long front lines for these small, numerous groups of divisions. Additionally, you still suffer the substantial increase to planning decay rate from manual attack.
I have not forgotten about the devevelopers talking about Wunderwaffen. Tbh I think Wunderwaffen could be a lot of fun and be a great addition to the game, especially if this includes a rework of jets to make them actually impactful, and things like Mulberry Harbors which were mentioned. A reason to race for The Bomb could also be really fun. However, as fun as I think wunderwaffen should be, I definitely thing some a new mechanical overhaul of logistics, planning, and defensive warfare(including entrenchment) is a much bigger priority. In my opinion. the DLC that is coming with 1.11 should focus on those three things. Peace conference rework/improvements and wunderwaffen could be for the expansion after that.
My two cents.