Well, not Khrushchev, nor Malenkov is liberal. But the one that you should know is L.Beria, 1st Deputy Chairman of the Council of the Ministers of the CCCP. Well, Beria was prosecuted for "serving foreign/Britain" interests, that means he's a liberal. I think if he came to power he will prosecuted Khrushchev and Malenkov (somehow), keep Stalin in Mausoleum and most of all, freed (nearly all) GULAG prisoners. He could let the Baltics independent and allowed German reunification in exchange for the Marshall Aid. Maybe Eisenhower/Truman supported it because this will increase the US interests by selling oil. I will make Beria's history in a positive way (which means that also change his OTL profile)
1. Marshall Aid and economic reforms
Since it became a market economy, Beria can get some money from the US. This will let to the CCCP's economic miracle like the Germans one. And maybe Soviet Union can be an ally with NATO (I won't think they will join, maybe they were neutral at least). Second, since he had became a leader, he will get the position of Prime Minister and First Secretary. Because he became a liberal, he still have some conflict with China. However, the Soviet Union had more weapons than the US, so the US may demanded to have less weapons. Beria may refused but he will signed the NPP, I guess. However, with liberal reforms implemented, that means a much less bloddy political struggle must occured rather than the opposite.
2. Political reforms
Beria, who now became General Secretary with a majority of votes, now decided to slowly, cautiously implemented the reforms he dreamed about. First, he let the Eastern Bloc free to go, let governments like in Poland (Bierut), Czechoslovakia (Gottwald), Hungary (Rakosi), Romania (Gheorghiu-Dej), GDR (Ulbricht) and Romania (Gheorghiu-Dej) defeated in democratic elections. However, democratic elections weren't made in USSR, as Beria thought that Russia may need a long time to completed her way to democracy. Mao Zedong, however, resisted the (atleast) captialistic reforms and decided to follow a Stalinist line.
Rehabiliation also were extended. Georgy Zhukov returned as commander of Moscow Military District, Nikolai Bukharin were unofficially rehabillated and his views were implemented on the CPSU.
In 1956, Kim Il-sung, visited the Soviet Union as the delegation head of KWP in 20th Congress of CPSU. As a result, pro-Soviet factions, led by Ho Ka-i and Pak Chang-ok, began a coup d'etat and declared Kim Il-sung wasn't leader anymore. When Kim Il-sung returned, he realised it was too late too stop. Under pressure from Khrushchev, a opponent-ally (somehow), the DPRK government had to implemented reforms and unified with Seoul government in 1965. Beria would continued his reforms as expected and he resigned in 1963, led his opponent, Khrushchev, came to power. Khrushchev was in weak health, so Anastas Mikoyan, Frol Kozlov had to assume the leadership instead.