The USA undoubtedly wouldn't have got that much money and power without a war but was still possibly the greatest economy in the World, and being able to keep trading with Europe in the 1940-1945 period, and generally being able to trade with more countries assuming that communism didn't expand a lot should be nice. Plus the US wouldn't have to spend a lot on its military or in OTL Cold War contests like the Space Race.
Stalin dead. Reformed government. What that looks like is anyone's guess.
Hitler dead. Reformed government. Even a demilitarized Wilhelmine cloud cuckoo land would be better than the criminal Hitlerite regime, though one would hope for a socialist bureaucratic state a la the Nordic model.
Civil rights mess cleaned up. Government reforms to the corrupt civil service. Social justice for minorities finally. Plutocracy regulated. Peaceful dissolution of the colonial empire.
Kill the war criminal emperor and the junta. Assert the supremacy of civil authority. Give women the vote. Smash the Zaibatsus. Demilitarization. End the China aggression. Make trade trade; not war war.
Kill Mussolini, then see Germany, except that a French style presidential system might be preferable.
Dissolution of the empire with far less fuck ups than we see IOTL. British reforms follow same wish list as the United States.
De Gaulle.
Keep the space program and fund it more. New Frontier is a thing and it works well with the American mind set. Besides the tech fall-out is a winner for humanity in general.