Unfortunately nothing will change for the North Korean citizens.
The only hope oppressed people such as these have is if the leader dies totally unexpectedly. Then there is a power vacuum, where in hopefully a more moderate regime will take over or even better, the people would sieze the opportunity to revolt and obtain real change.
In this case KimJong-Il has spent the better part of his dying days grooming his son and making sure those left behind in positions of power, will honor his son's authority. The onle hope the North Korean people have is that the son isn't such a nut-bar, which is very unlikely.
That said assassinating the son while the country is in mourning, as well as a state of flux and the resulting turmoil could provide an opportunity for a more moderate regime.
