Should South Korea and North Korea be unified?
I do not think it is possible, or at least not a good policy, to unite the two Koreas. Some of you may have noticed that starting in the Protected content , many South Koreans abandoned Confucianism and Buddhism and embraced Christianity, mostly American Evangelical Christianity. And by Protected content , the majority of South Koreans are Evangelical Christians. This adoption of American culture has fundamentally changed the behavior of South Koreans, who behave more like Americans than traditional Orientals like Chinese or Japanese. For example, many young South Koreans no longer take care of their elderly parents but leave it to the state to take care of their elderly parents. Not taking care of one's own parents is not allowed by Confucianism.
On the other hand, North Koreans have been culturally static for the past 7 decades. North Koreans will surely be shocked to see the behavior and lifestyle of South Koreans. Thus, it does not make sense to put a hen and a duck under the same roof.
The West Germans and East Germans did not undergo any cultural revolution between Protected content 1989; therefore, the two Germans could smoothly come together as a nation. If you think that the cultural divide between Americans and the British require them to live as two different nations; then, I am afraid that the cultural divide between the two Koreas is much bigger.