Re long-term stuff, I can see a couple of things:
- I think that unified Korea will see major development - while its involvement in the Vietnam War is butterflied away, there were other factors leading to the Miracle on the Han River. Plus, with North Korea, they'll have access to major rare earth deposits, which will make Korea majorly important for tech.
- I can see an earlier Korea-China rapprochement with Mao gone. While - unless they royally screw the pooch - I see the CCP still holding power, the more moderate government we see ITTL will probably be easier to open dialogues with at an early stage, plus there's not going to the same animus there as there is IRL for North Korea's government.
- Japan and unified Korea will be the big players in 'capitalist Asia'.