The Czar agrees that North Korea is of interest to China, if nothing more than to put into play a major distraction for the US, Japan, and South Korea. Gosh, if North Korea fell, those 3 economic engines might start railing on us to reform!
However, the question is, how important is North Korea to China? The Czar suspects that, while useful, the Chinese have more to gain with a unified South Korea. Worry or panic? Some of the few living old-schoolers might be concerned, but China did not fall when Mongolia went pro-West. They do not appear terribly upset by Afghanistans turn away from Islamism to something we hope approaches Western democracy. Bhutan, Nepal (well, for the most part) are not Chinese puppets, and off-and-on enjoy good relations with the US. It is always difficult to analyze what they think of Russia, or of Russia siding too briefly with us in the 1990s. For a while, all they had was Vietnam (ya cant count the Burmese pirates as commies, can ya?).
When does political ideology become less useful than economic reality? North Korea may be more useful as the drunk neighbor next door making your messy backyard look good. But perhaps you would not be too upset if they moved out.
Божію Поспѣшествующею Милостію Мы, Дима Грозный Императоръ и Самодержецъ Всероссiйскiй, цѣсарь Московскiй. The Czar was born in the steppes of Russia in 1267, and was cheated out of total control of all Russia upon the death of Boris Mikhailovich, who replaced Alexander Yaroslav Nevsky in 1263. However, in 1283, our Czar was passed over due to a clerical error and the rule of all Russia went to his second cousin Daniil (Даниил Александрович), whom Czar still resents. As a half-hearted apology, the Czar was awarded control over Muscovy, inconveniently located 5,000 miles away just outside Chicago. He now spends his time seething about this and writing about other stuff that bothers him.