What are the best results he and his successors (probably still his son) can get?
This would put the initial reforms in the agricultural sector in about 1979, with freedom for small, medium and then larger enterprises growing through the 1980s and 1990s.
Kim's reforms have "Korean characteristics" even though they parallel China's reforms in broad strokes.
North Korea is still very nationalistic and considers itself "best Korea" and remains absolutely a one-party (and maybe one-family) state.