Soviets have better officer training and mobilization planning in the 1930s, implement universal military service earlier than IOTL. Kulik dies in a plane crash, so that while the Purges still occur, the de-modernization program does not. The Red Army rebuild its officer corps and, while it remains fearful of Stalin, it remains quite competent. The Red Army wins in Finland, at a cost, and utilizes it's experience to conduct graduated improvements. When Hermany invades in 1941 it fails to advance past the Border regions, and from 1941-42 is bled white. From 1942-43 the Red Army conducts a steady reduction of German strategic depths, culminating in the collapse of Nazi Germany and the advance of the Red Army to, and beyond, the Rhine.
German Revolution 1918-1919 succeeds
Hmmm, never thought of that. You could even have Stalin feeling more confident with the Red Army and attacks Nazi Germany when the Wehrmacht is still fighting in France.
Pretty much this. The absolute earliest Germany can go red (assuming a PoD after 1900) is around the summer of 1919. The last real opportunity was probably around 1921.In my TL I took a middle-of-the-road approach, seeing as to how 1918-19 was to early for a successful communist takeover while 1932 was too late by setting the successful communist takeover in 1923 (with Red Army intervention) when unrest in Germany was high due to economic and political unrest, with the KPD being markedly stronger by 1923 to the point where IOTL it was capable of temporarily seizing control of certain sections of Hamburg.