Are you sure that the Koreans want to live in such a world? I'm not sure. Moreover I don't like the world in which maniacs possess nuclear weapons and not only mock his people, but threaten other countries. Jerzy Kim should be destroyed and nuclear weapons of North Korea must be liquidated.
Destruction of Kim Jong Un is not that easy. He commands an army of almost 4 million people, and these people are ready to die for him. You need to analyze whether 5-6 million deaths (may be much more) is OK, if you want to topple Kim Jong Un. For me, it will be better to maintain a status quo, rather than causing the mass murder of so many people.