Bolshevik-Socialist-Revolutionary-Narodnik Soviet Union. Gets rid of a lot of the rebellions against USSR.
So basically no forcible dispersal of the Soviets after the October Revolution? This would leave the Mensheviks around at least.
That would require Lenin to have a personality change, or someone to restrain him.
Shortest civil war is the Bolshies getting crushed IMO.
And the Belarusians, Ukrainians, Turkic peoples, Caucasians would still secede.