There's no black and white. Absolute good, absolute evil, and absolute normal are all things we see through an unrealistic set of lenses. Even the most psychotic of people have a warm and cuddly side, and even the best of us can be turned into monsters under the right circumstances. Un was "groomed" to be the new leader primarily after he returned from school, and there's a reason his father chose him over the alternatives. What that reason is, and exactly what type of person Un is, we can only speculate on. Based off of my limited perception, however, I can't say that I'm too impressed with him.