I would actually say the USSR could have done better under Khrushchev if he managed to stay in power, which if he didn't have the idea for misses in Cuba or that it blew up that the Politburo wouldn't have called for his resignation. Khruschev also wanted a more "freer" second world and did experiment with market socialism, all that went with Khruschev, even with Stalin's purges.
the problem is Stalin's willingness to put others either under the bus or on the back burner would really dog his successor who has to deal a fed up Mao. I'd would argue that the Korean War was the last straw as far as averting the Sino-Soviet split went. Basically, Stalin only gave his support to Kim, if Mao was going to help and basically let those two the heavy lifting despite assurances. If Stalin could die earlier before the Korean War breaks out you could possibly keep the Second World as a much more stable force.
There was a coup attempt against Khrushchev in 1957, which he barely survived. So Khrushchev could not have done anything more than he did regardless of the Cuban Missile Crisis.