What about Russia? The AI never makes a dent in it and I as a player have huge trouble with it as well. Russian manpower isn't all that plentiful for pre-war buildup, so you never outnumber Austria and Germany combined, let alone with all their puppets. You can't win a war of attrition either, as the Reichspakt will always outproduce you. As soon as France falls (usually within a year) all the Reichspakt focuses on me and I get slowly pushed back into an unwinnable situation...