As to some specific questions to narrow this down, was there any way to goad Hitler into declaring war earlier than OTL? Like invading Romania on top of Finland, shelling east Prussia kind of like the N. Koreans did to the S. Koreans as a provocative measure some years ago, ransacking the German embassy in Moscow and holding all the German diplomats hostage. Anything that would set Hitler off, and make him do something incredibly stupid like declare war on the USSR before France has even fallen.
And what would the effects of wartime economic mobilization and open mobilization of the army be -- like beginning after Germany declares war on Poland-- (I'm sure this might send Hitler over the edge on top of any number of other things)? Open mobilization is IMO a prerequisite for stopping the German army at the Dnepr-Dvina line. Bryan Fugate explains this idea in Thunder on the Dnepr (in his book he discusses the very intriguing three Kremlin/RKKA war games that happened right before Barbarossa)
And what would the effects of wartime economic mobilization and open mobilization of the army be -- like beginning after Germany declares war on Poland-- (I'm sure this might send Hitler over the edge on top of any number of other things)? Open mobilization is IMO a prerequisite for stopping the German army at the Dnepr-Dvina line. Bryan Fugate explains this idea in Thunder on the Dnepr (in his book he discusses the very intriguing three Kremlin/RKKA war games that happened right before Barbarossa)
Had the German advance been held at the Dnepr and Dvina Rivers, and had the Russians been able to concentrate their strategic reserves properly on the flanks of Army Group Center, in all probability the war would have been over for Germany as far as any offensive efforts were concerned. The worsening weather--first rain, then ice--in October and November could have been the curtain raiser for the counteroffensive by the strategic reserve against the exposed flanks of the Central Army Group. This counteroffensive, as fate would have it, came neither in October nor in November, nor did it come in the area of the Dnepr and Dvina Rivers. Rather, it came in early December at the very gates of Moscow.