I feel so sorry for the rank and file North Koreans every time I think about that country.
As far as one of the NK 'inner circle' being executed though ... I only hope it hurt.
I'm less certain about this being the usual shakeup. There was a lot of talk that he was very well traveled and had stronger connections with the outside world than most within their government. He'd have been hard pressed to make the current situation worse so what if he was trying to do something different? Obviously just supposition, but food for thought.
George Orwell's book "1984" (written 1948 and prior to the formation of North Korea) outlines a state eerily similar to North Korea with its erasure of people's past, punishment for not clapping enthusiastically and generally for "dreaming different dreams", as this article puts it. It's disturbing to see these kind of states still managing to transfer their totalitarian systems from generation to generation with no foreseeable hope of a positive change.
Most Western nations seem to be moving that direction as well.
This is like a modern day Game of Thrones.
His crime was being capable of displacing Kim Jong Un. Almost every monarch in history had a purge of uncles and male cousins.