Fun is the right word. Sort of, for speculators like us...now.
Some points :
The Kriegsmarine could have proved very effective on the southern side of the Ukraine, as much as unhampered transport. Sevastopol was quite a fight right?
Unlimited transport and trade always makes a bit.
The troops tied up guarding the occupied countries could yet have been haired down quite a bit. A few divisions at least. (The resistance does not have an ally without the UK)
Anyway, just two divisions (with all the fuss it takes to sent them to Africa) would have meant more than pocket change in the outskirts of Moscow.
The Time, yes. Well, although the Germans couldn't have moved before the spring thaws, - they were still a month or more behind the optimal moment.
A month only would have made quite a bit.
The airpower. Ok, the Germans lost 1200+ aircraft just in the BoB. 4 months. Experienced crew. And then again they had to keep an airforce from Norway, through Denmark, France and down south.
The Italians. Imagine that the Eyeties had aided much more on Barbarossa with Aircraft and naval power instead of jostling with the Brits.
And...the sense of realism. If the Brits had withdrawn, would Stalin have come more to his senses? Tough one
