I see a range of possibilities:
Likely
1) Peaceful, though drawn-out successful by Kim Jong-eun
2) Peaceful succession by Chang Sung-taek (though not so peaceful for the Great Successor, since it would probably involve a bullet to the brain).
3) A military coup, involving the ouster of the KWP.
Possible, but unlikely
4) Emergence of another KWP insider
5) PRC invasion (unless the new leadership turns its back on Beijing)
Sheer bloody fantasy
6) Disestablishment of Juche and Military First programs.
7) Revolution
Unification
In the short term, I see no potential for revolution. While there are certainly a large number of North Korean emigrants expressing enormous dissatisfaction with the state of the country, they still appear to be a minority in comparison with the size of the army and the population in general. How widespread is discontent in the population? Well I imagine (but cannot know) that hunger and large scale imprisonment of political prisoners has created a widespread malaise. But is that enough to spark revolution? So far as I can see the only organ capable of formenting revolution is the Army. And why should they rock the boat now? Only if the KWP tries to move the system away from "Military First" would be see the interests of the Army threatened.
But (and this is a big, "But") if ongoing crop failures continue to put the food supply in jeopardy, then someone is going to have to bite the bullet and look at further market reforms--in agriculture if nowhere else. And with private interests in business, information will inevitably follow.
Elections are not enough for democracy. Democracy is not enough for individual freedom. If the North Koreans follow the Chinese model, however, and create a degree of economic freedom, they may still be able to maintain their stranglehold on military and political power.
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--James