Kim Jong-un has a living brother and 2 sisters that can shift into Dear Leader so I doubt the Kim dynasty will be losing control of the DPRK any time soon. The sisters, both of whom are members of the party and both are probably just as ruthless as their brother. The youngest, Kim Yo-Jong, is the Director of the Propaganda and Agitation Department of the Workers’ Party of Korea. The oldest is also active in the propaganda ministry and is a Lt. Col. in the army. The NK Kim dynasty has survived 2 previous dear leader deaths, I see no reason that it wouldn't survive Un's. Unfortunately, any change on leadership that does not see the whole family and party removed is unlikely to result in any improvement for the people of North Korea or the world at large. If anything, a more competent and less dilatory member of the family taking the reigns is likely to make at least the international situation more dangerous. The only way there will be real and significant change in North Korea is if it merges with South Korea under South Korea's democratic system.