From my experience, I cannot agree completely. The Soviets smash the Germans in about 50% of my Games (except when I play the Reich ^^), It also happened some times, that the timid Germans didn't dare to invade the Soviet Union in 1941, only to be invaded by them about mid-1943 and be crushed in late 1944. So far the funniest Game I had was when Germany decided to back off in "Danzig or war" and lived in peaceful coexistence with it's neighbours.
China however, is indeed conquered by the Japanese Empire every single time, usually in late 1939. Maybe there should be an event which simulates Maos rise to power against Chiang Kai-Shek and the Kuomintang by giving bonus ressources and IC to Communist China, or via some "province X defects to Communist China" events similar to Vichy France's loss of provinces to Free France, followed up by an increase of production or fighting capability for the Chinese similar to the "Pearl Harbor" event for Japan.
I never had Japan attack the SU, even when it was ripe for the taking because of the Germans smashing the Russkies to kingdom come. Personally, I don't see the need for the Japanese, to attack the US when they already have taken China, which was always their goal. Historically, Japan in it's own recognition had no other choice than to declare war on the US after they cut off Japan with their stupid embargo. The embargo was actually intended to force the Japanese to make acknowledgements and fold to the wishes of US foreign policy. Instead it was percieved by the Japanese as a severe humiliation (bad idea!) and an attempt to cut them off their vital ressource supply, on which they relied hard, having nearly no ressources of their own.
So if Japan conquers the whole of China, there would be absolutely no need for them to declare war on the US! On the contrary, it should be far more likely that they try to get a piece of the cake that is the SU, beating an already weakened foe and aiding their German allies at the same time, instead of risking the wrath of the Allies!
I would really love to see some improvements in these discussed areas, since they are indeed crucial for the Game as a whole.
Cordial greetings,
Agin