With the new progression system announced that could possibly delete the old campaign system through merging into a single pool that’s actually concerning for various reasons such as Axis players possibly not having an option to pick which theater of the war between Eastern and Western front incase an Axis player doesn’t want or not in the mood to face either Soviet SMGs and tanks or American planes or those that want to play early war instead of late war.
My suggestion is to have checkboxes on which campaign a player wants to play with 3 theaters of war then within it options with early, mid and late war while players that want to play any campaign can just check all campaigns and time periods in the options.
For Eastern Front:
Early war - 1941-February 1943(Stalingrad)
Mid war - After Battle of Stalingrad to end of 1943
Late war - 1944-1945(Everything covered including Berlin)
Western Front:
Early - North Africa and Italy
Late - Normandy, Hurtgen, Battle of the Bulge up to the end
Far-East
Early - Possibly 30s Manchuria and China, Khalkin Gol, Lake Khasan up to the fall of the Philippines(Bataan)
Mid - Midway, Makin, Guadalcanal, etc
Late - 2nd half of Philippines campaign, Iwo Jima, Okinawa and even Manchuria, Sakhalin and Kuril islands.
Sure there are problems in equipment where there are certain weapons and vehicles that were only introduced in certain time periods or battles like PPS-42 was never used in Moscow, Tiger H1 in later parts of North Africa campaign, IS-2 obr 1944 introduced in late 1944, Kriegsmodell and various Volkssturm guns introduced in 1945, etc.
Also allow presets for each period especially vehicles since Soviets didn’t change much in small arms from early to late with some additions like DPM and PPS-43 since the significant difference for them being vehicles(From T-34-76s and KVs to T-34-85s and IS-2s) also Germans using guns like MP40 and MG34 in all campaigns involving them even though they have different vehicles on the later parts of the war compared to early war ones.
I have to suggest this with the potential variety of issues that’s going to be created by the new progression system like Battle Pass missions asking the player to play a battle in a certain campaign for a number of times alongside future event missions involving playing certain campaigns like the most recent being the Stalingrad event making players do tasks in Stalingrad campaign only.