I think it would be a grave mistake to reunify. I think China, working through its servant NK, would proceed to turn SK commie and rob them of any and all natural resources and technology secrets.
The commies of China and Vietnam are not the commies of yesteryear where they were closed societies with long bread lines and the populace was being murdered by their own governments. The closest thing we have to that today is Venezuela, Cuba AND NORTH KOREA. China and Vietnam are very prosperous and open as compared to the 70’s. They’ve learned how to better brand communism and make it more attractive.
North Korea will not “rebrand” itself overnight to accommodate a reunification that benefits all. Communism is to benefit itself. The South Koreans will be so screwed if they allow it to happen.