Skip to a few years ahead, Kim Jong-Il dies at the age of near 100 or something. His son seeing how better off other countries are, abandons the juche idea, and transforms the autarkic state into something like China.
Now in China, many companies see no obvious profit from having factories there as the standards of living rise, so do the wages and taxes, and of course increased cost to factory owners. They would then relocate to their own respective countries, to reduce transportation costs. This would possibly damage China's export economy.
Looking to Iran next, the Second Iranian Revolution which happened around 2011 changed the country to a more liberal one.
Checking on Venezuela (and other more hostile oil rich countries for that matter), as price of oil rises, and with peak oil already passed, many developed countries opt for biofuel, like E85 and other alternatives, such as fusion. With money no longer flowing like oil, they would have reduce spending on the military and more on long term investments and other sectors to create more sustainable jobs.
Russia being Russia, they won't attack unless it involves their own claimed land (like Chechnya or Ossetia).
Which leaves some potential candidates, which is India, Pakistan, the new Egypt, and of course the US of A.
India and Pakistan for obvious reasons, they are like the Koreas, only with more nukes, tanks, planes and men. Egypt probably would take on Israel to make up for what they see as a betrayal by Mubarak for being so western friendly. And America has a very large armed forces. Plenty to put in more puppet states and raise up a few friendly dictators to replace the lost ones. Problem is would other countries let America install more dictators? Maybe Russia would want to put their own dictators instead. That or I'm betting on a drunk starting WWIII.
Or Google finally made its droid army and starts conquering the world in a friendly and evil manner. Which Microsoft won't take lightly, and send in their clone troopers. Mixed in the fight are Apple's Jedi knights.