1. Italian Solo as listed above, but with dynamic or victorious ending with no RSI and such. Few people would want a losing campaign copying history
2. Soviet Grand Campaign, but starting with Moscow 1941. What happened before, makes no sense as we cannot simulate that within realistic limits. Again, no one wants to lose entire armies and follow such orders which demand the sacrifice your units - and on top of that you'd end up in front of a firing squad anyways.
3. German campaign starting with Kursk, on a semi-hypo path with branches (Leningrad, Murmansk) concluding a soviet-german ceasefire or a late Moscow.. perhaps late-war Sea Lion ala Panzer General style to put an end to the West as well... Meanwhile scenarios can be air-war over France or the Reich that affects later supplies/new units.. etc.
4. USA (or allies) West from Torch to D-day. (sure it's a must) Including air-war related stuff as well. Or make that a separate Air campaign!
5. Hungarian long campaign - but I'd do that personally so this does not count

. Also it requires "change sides AI trigger" and "unfriendly ally" features I mentioned in another topic.
6. Battle of Britain with the Luftwaffe concluded with Sea Lion. Let's suppose the Soviet did not prepare for attack in 1941, that required to silently cancel the invasion of the British Isles.
7. On a second thought, Soviet Early Grand can be done but with severe masochism level.

YES, you do need to sacrifice a lot, YES your own "unfriendly ally" NKVD division will attack you if you don't fulfill your objective - or try to retreat you will be decimated. YES with stupid AND/OR impossible objectives requiring you to struggle for secondaries or lose dozens of units trying the impossible. Escape "Butcher" Zhukov's slaughterhouse tactics... End up fighting the war with zero XP conscripts and volunteers (as it did happen) - end up purchasing new units more often than reinforcing the current ones... and forget elite reinforcements!

YES, have such leaders which give negative effects and cannot be removed! Win the unwinnable and be subject to rivalry and betrayal from above... find yourself to be sent on a suicide mission as result. And many more that came along with the biggest defeat of human history - and to the biggest turning point in history. Specializations what might give negative effect - or eliminate a general negative effect in the campaign (for example a general "quick retreat" trait of all units, or low efficiency "curse" or unreliable trait simulating low discipline, etc). Well it's just darn hard to simulate capital level of disability
8. Yugoslavian partisan war - not easy to do but perhaps worth it. Also needs the "unfriendly ally", "change sides AI trigger" and "civilian force" features for full effect
EDIT, to 7. I forgot CONTRADICTING objectives, where you may chose to lose primaries but live or get a result or outcome better for the future with secondaries (non-suicidal branch of the campaign, more points, units)