Couldn't the SU with it's multitude of 5 year plans lead to it being able to take on the Fascist Bloc?
If you're assuming a Germany that spends the 40's in a non-belligerent, slow, methodical buildup, it's implausible to assume the Nazi's run the show. Thus, your POD would have to be in the 1920's. Perhaps another Fascist movement would take over, however, any Germany that grows would have much better success by appearing less threatening. Thus, the longer you delay war, the more you must decrease the plausibility of autocracy in Germany. To make it to the 50's with a strong Germany that hasn't seen war w/ other nations since 1918, you almost have to assume democracy survived. The conditions that created and built the Nazi party (and any other party bent on dictatorship,) were such that it would be very difficult for a party to seize power and hold it without taking drastic measures. Thus, dictatorship in Germany in the 30's -> Overheating economy no later than the 1940's -> Earlier WW2 with a Germany facing more foes.
A democratic Germany would be on a slower timetable should it pursue a Pan-Germanic state, but with the right leadership, Hitler's pre 9/39 gains could be plausible by 1940-43. A Germany hellbent on a contigous state may (bordering ASB here, but...) be open to a straight-up swap with Poland. In that case, Poland MIGHT be open to negotiating away the Danzig Corridor should Germany realize the only way to have a contigous nation is to trade away the Memeland, (though I'm highly skeptical this is possible.)
In any case, put a democratic Germany who has fulfilled smaller territorial ambitions peacefully by 1942 next to a friendly neutral like Poland, and it's more plausible as the rest of the 40's go by to see a Western European anti-Soviet alliance. Intact Germany + France, the UK, Poland (who would be no joke had they been able to modernize,) and possibly token Spanish and Italian forces vs. the USSR? Poland, the Baltics, and eastern Prussia would get chewed up, but you'd be looking at a Western victory in a few years, plus a German atomic bomb program that has all of those Jewish scientists, possibly working hand-in-hand with French & UK programs.
That's my $0.02, anyway. Longer wait for WW2 -> Higher chance of democratic Germany. Democratic, sane Germany -> More intra-Western cooperation. Thus, later USSR vs West WW2, greater chance of USSR defeat.