I would like to better justify it but I find the absence of the primer cartridge technology somewhat frustrating and also the industrial-era units which, as history teaches us, certainly did not have flintlock rifles. What I am asking is to add a unit to be unlocked from trench warfare technology or similar in the skill tree just before arriving in the contemporary era, representing at least the soldiers of the First World War with the single-loader rifle. It is VERY important for history accuracy. I find jumping from early 19th century to mid 20th century military equipment a bit much, don't you agree?