Kim Jong-un was IIRC educated in Switzerland.
But he at the moment has nothing to his name which would justify him the future title of Great Leader. Given the history of the DPRK, and the huge manipulation of situations with the intention of giving Kim Jong-il the legitimacy to succeed his father, I can see this being another set of manipulations fomenting a crisis, which - at least as far as the DPRK internal propaganda will go - will be defused thanks to the "brilliance" of Kim Jong-un.
From the rest of the world's point of view, I think KJI's oldest son, Kim Jong-nam, would have been the better choice for a successor - he's long been an advocate of the DPRK implementing Chinese-style reforms, which KJI has always opposed. I've read that Kim Jong-nam prefers reforms along the Vietnamese model, which could also be a good thing, from the West's point of view. But who knows, perhaps Jong-nam is holding his cards close to his chest until daddy dies, and only afterwards he will announce reforms of the Chinese style (we can hope, anyways).
War: I doubt DPRK will actually start a war - they know they've lost the ability to win a war already in the 1980s. I think their main goal is the survival of the regime, and they know that war means the regime ends. China won't help them and they know it (in fact, thanks to wikileaks I know that China's preference is a reunified Korea governed by Seoul; it seems that only Japan desires the division of Korea to continue).
Last thing, I have to wonder... Kim Il-sung already in the early 1990s was considering reforming DPRK along the Chinese model. By then, KJI had already cemented himself as the successor (manipulating the situation to ensure that Kim Il-sung chooses KJI over his brother Kim Pyong-il), and there are quite a few rumours that KJI had his father killed... I have to wonder, had Il-sung chosen Pyong-il to succeed him, how things would have developed... or had Il-sung announced earlier his desire to reform, Chinese-style... things would be very different now, I'm sure. (KJI might even have become a star, a world-renowned movie director...)
In any event, I'm fairly confident that the most that will happen is some minor skirmishes, nothing worse than things that have already happened over the years. Even if KJI orders an attack, I don't believe the Army brass would comply. I think the sooner KJI dies, the better - because then Jong-un can start the reforms. Chinese style or Vietnam style doesn't matter... both will mean some significant change and integration into the world.
One last comment. This probably won't win me many friends here, but I think my username already succeeded in that, so doesn't matter
... Juche itself wasn't such a bad idea - a desire for self-reliance is a good thing; in fact, until the mid-1970s, the North's economy was stronger than the South's. The
bad idea was/is KJI's Songun policy. And an interesting aside to it, in the last revision of the DPRK constitution, KJI had all references to communism and Marxism-Leninism removed...
So yeah, let's all hope some "accident" soon befalls KJI, and DPRK can start reforming itself. Jong-un has lived in the west, so there's a good chance big changes will come after KJI isn't looking over his shoulder anymore.