The problem with this "what would you do approach" is that some decisions are only revealed as flawed in hindsight. The other is that is pre-supposes godlike powers, in fact even the most powerful figures have limited information or influence over certain individuals or processes.
In the meantime, as for all the ideas raised so far:
1. No halt before Dunkirk
The Panzers had no fuel anyway
2. Not letting up on the airfields in the Battle of Britain
Probably not decisive
3. No halt order by Hitler on R&D that won't yield results within a year
The Germans have quite enough resources spread on projects that will not come to fruition as it is
4. No Operation Barbarossa
A good point but then Hitler might as well not fight the war!
5. No declaration of war upon the USA
Yes, but how much would it help in the medium term. Also only clear in hindsight - a Japanese attack on the USSR could have been very valuable to Hitler
6. Use of the V-weapons against the embarkation ports for D-Day
Yes, but decisive?
7. Use of the V-weapons against the bridgeheads in Normandy
Yes, but decisive?
- Melting pot strategy instead of racism:.
It;s just completely ahistorical, and ignores what the war is about, other than that I agree with you.
- Competition instead of synergy: The Nazis increased production and productivity by combining companies of an economic branch into huge monopolies.
Production increases but productivity decline in the late 30s. The natural cartellisation of the German economy and the drive to autarchy also stifle this.
In fact if there had been no war till 44, as planned, the Germans would have had a military economy up there with the USSR or the USA anyway. For all the German war economy's weaknesses I am not sure it could have been exploited that much more.
More subs, to allow an effective war against British shipping in case of a war against GB.
Yes, but also more planes, tanks and everything..
Quick development of tactics against German tanks after - An offensive against Germany within the first few days of the declaration of war, to quickly gain south west and western Germany.
The Allies are not ready for war, simple as that.
I figure it would be useful to secretely distribute old and damaged tanks, as well as some cannons, along the whole coast line,
Well, there is the Atlantic Wall...
Worker and Peasant's Air Fleet placed on alert
-Better logistics for Soviet counterattacks
-Better co-operation with Polish and Baltic states, possibly first do not occupy them
Definitely yes be prepared to meet operation Barbarossa - that is not a hindsight mistake.
Soviet logistics cannot be improved so easily however
As for the third, if you did that, you would not be Stalin
I will respond to more of these later, but many of these suggestions below were tried and failed, or constrained by resource difficulties