I was just comparing this AAR with the one of my game with KZ. The biggest difference is that in my game KZ used his uber-diplomacy on the US, while in this game he used it on Russia. But there are some remarkable similarities in how the games have progressed such as:
1. France was conquered on the same turn (July 21/40) in both games. Considering that France invested heavily in Diplo chits this is actually pretty good for France.
2. Malta was captured in October 1940 in both games.
3. Cairo fell in July 41 in my game and October 41 in this game. I believe this was primarily due to KZ putting a lot more quality units (including 3 tanks) into Libya/Egypt. This probably meant that Eng;and was wide open for Sealion.
4. Barbarossa was launched by me on September 3/41 and by Sugar on August 19. So rather late Rusian invasions for both of us.
It's true that, without knowing it, our game was kind of a rehearsal for this game vs Sugar.
You left out one similarity, I screwed up Iraq defense just the same.
Things I learned from our game that I changed in this one.
1-UK didn't invest in France defence. This ain't mistake per say to do so but for this particular strategy I couldn't spare the mpp. Germany slow progress there was in part the maginot snafu but also, unlike you, he didn't buy any additional offensive unit for France invasion relying on existing units. In the end, it compensated the lack of UK support.
2-I started my UK vital research and unit buys before going diplo. Advanced air and armoured warfare were both bought turn 1. Going for diplo too early made me lag in air tech in our game. Tech I could double chits were invested after diplo.
3-Put pressure on Italy. It take a little bit of time for Germany to deploy in NA so the UK has a window of opportunity to inflict some damage. I was too timid in our game and just waited on defense, letting you deploy in NA uncontested. Damaging the ports slowed the german deployment in this one and allowed me to destroy an entire Italian army group.
3-For my offensive punch, I went tank instead of bombers for the UK. Cheaper to acquire and maintain, not as dependant on weather. And more firepower once you get that second strike.
4-Higher priority at Command tech (double teching it to max) and improving HQ. I saw in our game how my airforce was easily wrecked despite having numerical superiority a lot of time. Half of that was that I was behind in tech, the other half was that my HQs had been neglected.
5-No forward defence for Russia. Went for Leningrad/Stalingrad and left it open in between. If you salvage things from barbarossa opening, it's a windfall but in the grand scheme of things, the border units don't matter.
6-Bigger emphasis on ramping up Russia production. No cashing out prod/industrial tech to start the inf tech early this time.