I see reasons for a human player to use Limited War now, thinking about the Germany-Japan situation (you don't want Sudden Death for Japan because their whole army gets eaten by the Soviet Far Eastern Front in Manchuria). I hope the AI knows that too (so, for example, Bulgaria could historically opt out of war with the Soviets - I'm VERY glad King mentioned that they thought of that...).
There will be no sudden death, because with Japanese help, I will destroy the SU by 1942, they might get weakened against the American, but that is a war I won't be heavily involved (other than defending Europe and air warfare)until I have a decent fleet