Ok, allow me to make a few clarifications:
Sub rules:
Only destroyers can hunt down subs, but when subs attack a fleet, all can defend, although if there are no destroyers, the subs can use sneak shot and then dive. The purpose with this rule, combined with the new convoy (convoys take immediate damage) rules, is to create more realistic convoy attacks. Otherwise, IMHO, there is absolutely no point for Germany in particular to employ subs, which is not realistic at all. Sub attacks on ships has been reduced to a 1 to ensure they do not become to powerful. Their primary purpose is to destroy convoys.
As for Russia $2 infantry, yes this is powerful, but remember they can only start using this rate once they go to war. And to offset this, the Germans are given the following:
1. Advanced artillery (1 artillery supports 2 infantry)
2. Mechanized infantry (German mech paired with a tank attack at a 2)
3. Stukas: Tac bombers do not need to be paired with fighters to attack at a 4