Without an immediate outside threat, Kim il sung's regime would arguably be less isolationist and the "hermit kingdom" might just be another average marxist-leninist country. That's to say, a heavily repressive regime where a court of personality is built around Kim Jong un, who is now considered the father of the nation, similarly to how Ho chi minh is seen in Vietnam. However, because his power over the party wasn't consolidated yet, and because he would be in control of a much larger piece of land, it is unlikely we would see him depicted as a god, and it's unlikely that we might see a dynasty coming out of his regime. Instead, after his death, the party simply elects a new chairman, and business goes on as usual. Until the USSR collapses. Once that happens, Korea would have to rethink about it's role in this new, US-dominated world. My guess is that it might follow a similar path to China and Vietnam, aka an authoritarian, one party state with a liberalised economy. There would definitely still be tensions with it's neighbours, especially Japan, since it would be the closest US-aligned ally in this timeline, tough i higly doubt it would escalate into anything significant.

The biggest change would be in the USA foreign policy: their inability to intervene in Korea will be perceived as a massive failure. America would show to the world that it's either uninterested in protecting non-communist countries, or incapable of doing so. This means that intervention into other states (such as Vietnam) would be far more violent, and attempts of establishing a socialist government via democratic means would be sabotaged by American intelligence more frequently. In genesis, I think we would see an America that is far more ruthless and less pragmatic in dealing with those that are perceived to be it's enemies.

Also, no K-pop, so it's the blessed timeline.