Two major fronts/ Maps/ sets of multiple maps could be added to Moscow Campaign.
This would give the campaign a “revival boost” and more depth while staying historically as accurate as possible with the current limitations provided.
- Brest Fortress.
Germans wanted the fortress because there was a railway choke point that they desperately needed, therefore this set could include the fortress itself and a railway/ logistics place connected to the railway. (At least 2 maps, with further work 3-4 new maps)
One of the most famous stands that the Soviet Union did on the front-lines, still a historical place where Belarusian s visit very often a tourist attraction for the population. Very heavily fortified area that would provide some fortress fighting for the Moscow Campaign.
- Leningrad siege.
Terrible nightmare that unfolded in the beginning of the operation of Barbarossa, KV-1 tanks were driven directly from the factory floor to the battle as soon as possible, some of them were not even painted.
Siege of Leningrad - Wikipedia
Leningrad area could be filled with many trenches that need to be stormed, Soviet counter-attacks, night fighting and ice-road.
Plenty of new map material there too, should provide 3-5 maps.
Also as a BONUS suggestion, new weapon (Premium and expensive like Suomi-sub-machine gun in Moscow Campaign)
Lahti-Saloranta LMG (Widely used by Finns)
Lahti-Saloranta M/26 – Wikipedia
Another picture for the road: