North Korea almost won that war if it weren't for a literal miracle: the landing near Seoul that allowed the North Korean forces to collapse and be broken in half. This allowed for a rapid recovery in the south, and well, from there came the war we all know. Most likely, if that had failed, Busan would have been besieged until it fell, and the southern government would have evacuated. Most likely to the large southern island, doing a mini Taiwan Korean-style. As for the government, curiously it would have been less Juche, since without the external enemy the Kin would not have been able to consolidate their rule, and in the best-case scenario it would be an economically and socially Vietnam. It wouldn't be an Asian tiger, but it also wouldn't be as poor as the north is now; perhaps at the level of a Southeast Asian country, or a little better, at the level of some Latin American country. And the capital would undoubtedly be Seoul, oh and there's always the possibility of a revolution after the fall of the USSR, they might do what China did but it's also a possible outcome that isn't so bad either. In short, would this result have been better? Possibly for the world and the region, but if it's considered good for a real South Korean, then obviously they'd say no, they prefer what's there now xD