@:urluckyday: While I think proliferation is to be avoided India already had the nukes, so I don't see the big deal.
@:Purifier: When one of those you end up upsetting is your chief ally, it's kind of a big deal. Also nukes are costly (just ask NK), risks proliferation (just ask Pakistan), and could at worst lead to sanctions and making it illegal for other countries to help you with your civilian nuclear program (just ask Iran).
@:Tot: I'm not saying it is likely, or that such a war would be on purpose, but when two countries lob shells/missiles at each other, things can spiral out of control. Also, NK doesn't want to rely on China, because in the long term, China's interests could change.
As for China, I doubt there is much schadenfreude involved, as they allready have to deal with north Koreans fleeing across their border, in addition to the other joys of having a dirt poor neighbor.
As for Taiwan (why not ROC? since you use PRC
), the difference between it and NK is that NK didn't risk being invaded by going nuclear.