Pak Chung--hee was assasinated if I remember right and was regarded as a dictator. I do think Kim Young-sam was decent, but there was widespread discontent with him too. It may have something to do with the Koreans too.
My remark was not concerned with whether they were LIKED - but only whether they were competent. Park Chung-hee almost by sheer dint of his personality galvanized the Korean nation, and inspired it to become a modern industrialized country. Sure, he was a "dictator", but not of the "tyrant" ilk. He was more imperious than dictatorial. He was single minded and relentless in the pursuit of Korean advancement.
Kim Young-sam was the natural heir of Park Chung-hee and made democratic norms part of Korean life. Both of these men have important legacies for Korea.
The last two Presidentas have been little better than North Korean agents of influence in the South.