I'm not sure if we'll have another WW2 game soon but if we do, we should include more factions. I loved how Rising Storm had 2 new factions (Japan and USA) and there are plenty of theaters that can bring new factions. They already have Russia and Germany on the Russian front and USA and Japan on the Pacific theater. They can include a French theater from the German/Italian invasion and include France and Italy as new factions. They could include an African theater with USA, UK/commonwealth, Vichy France or Free French Forces, Italy, and Germany. They could include the western front of 1944 with USA, UK, Germany, and Vichy France or Free French Forces. They could include UK/commonwealth in the Pacific theater with USA and Japan as well. There are many possibilities but they all include 7 major factions: USA, UK, France, Italy, Japan, Germany, and Russia.
The Russian, German, Japanese, and American factions have already been made with their weapons and classes but they can be tweaked to fit the time of a battle. For example: Germany could use the StG-44 if the battle is towards the end of the war or Germany can't use the PPS-42 if the battle is towards the beginning of the war. I have some ideas of weapons that Italy, Uk, and France can have if they will be used in future games:
France: French F1 grenade (different than Russian) Hotchkiss M1914 fixed machine gun Modele 1935A pisol Modele 1892 revolver FM 24/29 light machine gun MAS-38 submachine gun MAS-36 rifle Berthier M1916 Fusil Automatique Modele 1917 rifle Berthier M1916 sniper MAS-36 sniper