Imperialist
Of course it's Your AU, so You can invent (almost) any excuse You want for things going some way rather than the other, but I see some issues with Your plans.
One thing is "Gradual increase of (total war) production prior to start of WW2" - problem is, that when Germans started the war, they were unaware they just started a
world war. They expected it will be just Germany (and Soviet Union) vs. Poland and therefore saw no need to increase their production efforts - which resulted in the fact that in Poland they nearly completely exhausted their ammunition stocks, but that's another thing.
What's even more important is that pre-war German economy was on the brink of disaster - it was simply overheating because of rapid rearmament, running out of money and starting the war (or rather: taking over some other economy's resources) was simply an urgent necessity.
On the other hand, theoretically it is possible to see a situation where Great Britain (and France) do not declare war on Germany on 3rd of September 1939. To put it shortly - after the annexation of Sudetenland in 1938 Hitler declared to western leaders that Germany has no further territorial interests. When nazis annexed rest of Czechoslovakia (creating Protectorate of Bohemia and Moravia and "independent" Slovak state) as well as demanded transfer of Klaipeda from Lithuania in March 1939, the western leaders felt Hitler went "a step too far", which resulted of guarantees of independence (though, interestingly - not of territorial integrity) for Poland that in turn caused British and French declarations of war on 3rd of September. Therefore, if there was no annexation of Bohemia and Klaipeda
before war with Poland, then
perhaps UK and France would not gave any declarations to Poland at all and and would not declare war on Germany. Downside of this theory is that Germany needed Czech economy - particularly military industries - to start that war with Poland in the first place.
As for the strategic bomber force - main problem with creating such force is that it's horribly material- and industrial-capacity-intensive toy (not mentioning personnel issues). Btw. if I remember correctly, German rearmament plans called for the force of 16 fighter, 16 heavy-fighter (Zerstoerer), 16 dive bomber and 58 bomber
geschwadern to be fielded by the time the World War was to begin (they expected it will start at some point, just thought it will be rather 1942-1944). But of course, like the
Kriegsmarine's "Plan Z" - to which it was
Luftwaffe's counterpart - this program was a total fairy tale for many reasons.
And finally - the only difference in length of war would be dictated by "when USA will get first functional nuclear weapons".