This is my idea for classes.
Assault-the main soldiers of the war. Equipped with bolt action rifles, maybe some specialty guns. Can use pistols.
Officer(Engineer)-Called officer for the purpose of name only, no command benefit. Use shotguns, lever action rifles, and maybe semi autos. Can use pistols and swords.
Support-Like the name implies. Use LMGs/SMGs (Lewis, Chauchat, MP18, BAR, etc.) Can use pistols.
Sniper-Uses scoped bolt action rifles. Only class that can use scoped weapons. Can use pistols.
There should also be a limit on how many classes per team (a lot of assault, a few officers/snipers, and a medium amount of support)
There should be a buy system where you are "issued" some weapons and have the option to buy weapons with in game money like troops did in the actual war.(Creds to ImBeauski for idea)
Ideas? Thoughts? Comments? Feel free to share