They were too late in sharing the U-boat tech as half the war was almost over.
No point in that since the Germans managed to field their newer and superior designs themselves only when half of the war was over and the battle for the Atlantic was lost. Also at least in some regards the japanese sub technology was not that much inferior, for example it was a japanese sub that managed to reach the highest submerged top speed during the war.
The japanese navy did not emphasize submarine warfare as much as the Germans did due to different doctrines. Even the Kriegsmarine only managed to shift its ressources fully on submarine warfare when it was already too late.
A Russian double agent who managed to convince Stalin that Japan would not attack.
It would not have needed such an agent since the Japanese had very clearly no intention to march against the Russians at all. This is mainly due to experience in fighting russian troops prior to WWII. My guess is that Stalin would have seen that himself quite soon.
There was nothing wrong with Hitlers tactics really, he was just an 'evil genious'.
I fail to see to this very day the reason for the view of Hitler as some kind of genius, especially in the military sense of the word. A view that seems to be very persistent outside Germany, yet not so much within. Hitler was to some degree a gifted character concerning politics and especially rhetorics. Also he mostly shared the view of his time and the german people concering some major social issues. However he had no special military gifts whatsoever.
That shows up very clearly in several of his decisions concering vital tactical and strategic planning:
The halt in development of rocket technology after the invasion of Poland. Not foreseeing Britains entry to the war after the invasion of Poland (he expected the french decision for war though and was not worried about that). His approval of using the Luftwaffe in striking against the BEF in place of the army. His decision of further development the Me-262, the most promising jet fighter of its time, as a bomber, therefore delaying fielding of the fighter for one whole year, allowing the allied strategic bomber offensive to continue. Not to mention his multiple mistakes in planning the military actions against Russia after he took over most of the planning from his generals himself.
Hitler in the beginning had the luck of having the right people in the right places. However after he took more direct decisions in the war and when allegiance to his person grew more important than military skill and knowledge, things went rapidly awry.
He ran out of people and then fussed to send the women into the work force, thats what screwed him up.
He would not have ran out of people if he would not have screwed up with some of his major decisions concering warfare, just ask the 6th army!
Also there was nothing wrong with the women. In fact they formed large parts of the industrial workforce and even homeland defence, thus contributing to the war.
It was however a major mistake to shift german industrial production to military needs and war time standards as late as they did. Mind you, german economy ran on peace time standards for the better part of three years into the war! Only when Albert Speer took over the planning of the industrial production in 1943, the german economy managed to perform incredibly, putting out equipment in sheer masses and all this at a time when ressources were already spread thin and despite allied bombing raids.
