Here's how I see it. USSR crumbles at the end of WW2. If that were to happen, you exponentially change the course of events.
For instance, just starting, you divide Berlin into 3 sections, not 4. There's no Berlin Wall, no Berlin Airlift, yadda yadda yadda.
Second, with the collapse of the largest Communist power, Communism appears less favorably. China might not go Communist. Without a Communist nation defying the idea that they can't exist, even a Communist Cuba might be gone.
There's a rush by various nations to carve up the remains of a chaotic and fractured Russia, although this will probably not spark any wars in a war-torn world.
The Marshall Plan may or may not come into existence depending on the President at the time. If we have a President determined to either be a good guy or gain support in the world, it might have happened.
But, quite frankly, the US needed the USSR to get where it was. If the USSR dissolved after WW2, there's no incentive to, for instance, go to space. And while you will stop some events in history, like the Red Scare, the bad might just outweigh the good.