No, we actually are in agreement in our assessments, we just have different expectations. Look at your statement of facts, that the Harimoto/Hayata pair has a history of being the "second best" pairing, and that the North Korean pair is of "equal and possibly superior strength". There is no disagreement there. I just don't see those facts being good enough for Harimoto/Hayata.
Hayata is the best non-Chinese women's player while Harimoto is arguably the best non-Chinese men's player. The combination of the two should be far and away the best non-Chinese pair in the world as beating the both of them at the same time should be doubly hard compared to beating each one individually. The only thing possible that prevents it from happening is if they don't work well together as a pair in doubles. In other words, the fact that there is a non-Chinse pair (IMO 2 pairs, including the SK pair) of "equal and possibly superior strength" suggests that they don't pair well together for doubles.