Yes, he was imperfect, and he may be some or all of those things. But he was also a person who believed in pushing South Korea forward toward democracy. No opportunist on this matter, he is a person who risked his own life to bring democracy to the ROK. Yes he was imprisoned and set to be executed by the despotic regimes he opposed. That right there earns him immense respect in my book.
In 1997 he finally won the presidency he had long coveted — in direct elections he had helped make possible — at about the worst possible moment in modern Korean history. And he was willing to scrap some of his notions of political economy in favor of the tough choices (and untested choices based on faith) that were necessary to bring Korea out of the chaos of the Asian economic meltdown.
When he became president, he decided that it was time to shift gears vis-à-vis North Korea. Some four decades of mutual hostility had not made North Korea less threatening, more democratic, or any friendlier, and he thought it was time to try killing with kindness. Reach out to the North, try to integrate them, get political and social change to come from economic integration. And so was born the "Sunshine Policy."
It's no surprise that they also couch his winning of the Nobel Prize as if he won it solely for his unprecedented 2000 summit with Kim Jong-il (about which Halmoni — whose clergymen father and brothers were killed by the communists — said upon witnessing that embrace on the tarmac that he should be arrested when he returns to Seoul), when the Nobel Prize committee specifically stated that his democracy activism was the major factor:
for his work for democracy and human rights in South Korea and in East Asia in general, and for peace and reconciliation with North Korea in particularLike Corazon Aquino in the Philippines (who may also have deserved a Nobel Prize), he was a major factor in the sweeping in of democratic reforms in East Asia during the 1980s. Lest one think that the "democracy and human rights" part was tacked on to provide cover for the summit being the real reason, let's not forget that just nine years earlier would-be Burmese leader Aung San Suu Kyi had won the Nobel Peace Prize "for her non-violent struggle for democracy and human rights."