The Man of Steel sticks around...
Off the top of my head, the resurrection of the Holocaust would definitely come to pass. Stalin was planning to cull the Jews within his borders when he died claiming there was a plot amongst them to kill him. An ironic belief since Stalin was the first world leader to endorse and recognize the establishment of Israel in 1949.
As to Stalin being psychotic, the man was simply a sociopath as well as a skilled politician. He wiped away a swath of personnel to make way for the next group, each time letting the newbies realize who held power. Should they become too strong, the cycle repeated. People were materiel to be used. It was understandable if he was a bit paranoid. The man made enemies! This style of leadership, if prolonged, could lead to a lost generation of future leaders. Who knows how ill-equipped Stalin's successors would be. On a positive note, Beria would most definitely be culled by 1955 at the latest. What that would mean to the NKVD is anyone's guess. Probably broken up and recreated in a new guise.
Stalin wasn't exactly the blood hungry, world conquering monster many thought he was. In 1952, the year before his death, he tried to push the policy of superpower disengagement, a policy where the two major powers, the US and USSR, remove their support of proxies in proxy wars in order to de-escalate a superpower conflict back to a local problem based on local disputes. This was meant to create buffers between the superpowers that might prevent conflicts or reduce the intensity of conflicts. This was supported by Stalin offering to let Germany reunify if it took the policy of neutrality between both superpowers. Give Stalin ten more years and he might actually convince the West of his sincerity thus bringing a thaw in the Cold War.
Just a few of my opinions...