As for treating the smaller countries better, I think the main problem is they're expected to do their own research and produce their own equipment. Things like the Commonwealth Air Training Plan and the use of British and American produced equipment need to be better represented, licensing doesn't go far enough. Australian, Canadian and NZ divisions were equipped to the same standards as the big powers - sometimes better. And hundreds of thousands of pilots and sailors served with the RAF, RN etc.
I could lecture for hours on the Commonwealth Air Training Program and Canada. My city was home to "Technical Training School #1, the largest air ground trades training camp in the Commonwealth. Men came from everywhere to train here. I bet if anyone of you from a Commonwealth country talks to a few WW2 Air ground crew veterans you will find half of them know or were trained here.
I have to agree with the above comment, very strongly. The commonwealth and a few governments in exile like Poland and the Free French were equipped as well as the major power. A special share technology and joint research for commonwealth countries needs to be added somehow to make the game historically correct. As an option of course.
As for Canada being 1/10 the population of the USA and having about 1/4 of the North America sales I suggest:
1) Canada has been going through a rebirth of military pride over the last 10m years.
2) Although not up to most European standards Canada does teach WW2 in its schools. The USA for the most part does a poor history in school lesson and world knowledge in general.
3) Canada has a strong European immigrant population that are encouraged to keep routes with their past country where in the USA everyone gets melted into baseball, hot dogs, apple pie and Chevrolet.
4) Canada has a long history of peace but when we rally around a cause we rally well. In WW2 we had little conscription compared to most European counties,and few conscripts ever saw front line action. WW2 is remembered as a time of great nostalgia. An era where we rallied behind a cause and took action. Even French Canadians were not opposed to the war, just conscription.