Maybe no Stalin leads to much better Red Army, which leads to better performance in WW2. Thus the bigger German defeats create more dissension within the top echelons of the Wehrmacht. Therefore, there is more support for the July 20 plot, less indecision and backstabbing against the plotters, and because there is less indecision they activate the bomb on July 15, and luckily although Hitler was called away he doesn't reach the door in time and is incinerated along with Himmler, Goering, and many others. Valkyrie is a total success, and Beck negotiates with the Politburo, Roosevelt, and Churchill for a favorable and fair peace, which the Politburo persuades Roosevelt and coerces Churchill into agreeing with. Germany keep Anschluss areas, but pays heavy reparations, and their scientists are forced to give up all secret. Nazis who weren't summarily executed are turned over. East Prussia is still German, and a new government organized along Weimar-lines is instituted. Germany is to remain a buffer state between the Warsaw Pact and NATO, and both sides make damn sure they stay neutral.
Pacific campaign ends much as it did like in OTL, but earlier and with signifigantly less Chinese casualties, with the Red Army supporting the communists in Manchuria. The Cold War begins like in OTL too, with Space Race and Red Scare and all. CCP takes all of the Chinese mainland, KMT in Taiwan. Mao begins the Great Leap Forward, and tensions rise with the USSR until Deng Xiaoping and other enemies of Mao get sickened by the failure of the Great Leap Forward and Cultural Revolution, putting Mao out of power and imprisoning him for being 'counter-revolutionary' ironically enough, beating Mao Zedong to the punch. With a more Soviet-friendly (and sane) Chinese government, Sino-Soviet split is avoided. Kruschev or some other progressive premier allows for more immigration and other reforms.
Due to lack of Stalin the USSR is already dramatically different. Under Lenin the goverment was extremely liberal, with some personal freedoms even the West did not have (Lenin legalized every aspect of homosexuality I've heard, which was reversed by Stalin). Of course the press is still stifled, but it resembles modern China of OTL. The USA, during the Red Scare, tries to distance itself away from every aspect of the USSR, and due to less extreme Russia, America is the extreme one. Liberal politicians are stifled by either McCarthy, J. Edgar Hoover, or more simply the right-wing media as would be most common. The USA as a whole goes even further right than it did in OTL 50's, and is less popular.
Further down the line, Korean War is roughly similar to OTL, but less Soviet aid is sent and the US and South Korea suffer a bit less. However more reactionary US perhaps leads to them maybe even aiding S. Korean massacres of communist-sympathisers. This would hurt their world image.
By the time the Vietnam War comes around, less people are willing to help the extremist USA, and only their Asian allies give any assistance. The USA is even more aggressive, and launches more direct attacks on North Vietnam. However the USSR gives even more aid and so the USA suffers greater casualties because the NVA is better equipped and US tactics are worse and more direct. The right-wing leadership of America is shattered and more liberal politicians are elected as a result.
Finally, (if) when the Afghan War pops up with the Soviets trying to assist their communist Afghan allies, the more liberal USA doesn't give so much help. Also, perhaps Charlie Wilson is indicted and arrested on drug charges. Therefore possibly no US help.
How's that? Is it good, or at least plausible? Or should I quit?