Fundamentally they needed a communist Germany. Only a communist Germany would give any hope for the Russian revolution to not be internationally isolated, communist revolutions indigenous or based on red army rifles in eastern Europe would not have been sufficient.
Of course this operates under the assumption that it was a viable project at all. Which it wasn't if we disbelieve the claim human nature is inherently void and malleable.
A communist Germany, Communist Russia and by extension communist Eastern Europe would not have been free of problems. German communists and Russian communists would have competed for control of the new socialist state, and so would say Polish communists and so on. Under such a power Russia would likely have been developed still, but Germany would be the center of the state.
Absolute most likely is a spreading of communism as a revolutionary ideology in this scenario-to the colonial world, and China. The West(by this point the UK, France and the US) would have faced down unrest themselves, and likely would have coalesced together in anti Bolshevik bloc.
I suspect the US would also have had a strong tendency towards isolationism, "let the British and the Bolsheviks battle for the world, America must guard its own shores". As the ideology of anti communism as a world crusade under Truman would not have had the precedents to exist.
Assuming say France, the Netherlands, Italy and or Spain became communist or communist dominated-I imagine the US would have basically battened down the hatches, and the British would have become some sort of anti communist police state.
Possibly some sort of Anglo-American Union would have occurred(or vastly closer relations).
It would be a very different world, probably a much worse one than the one we have.