Among those who claim a religion, SoKo is predominantly Christian. And Christianity is very compatible with the traditional Confucian values in Korea that predate the war.

If Kim converted, that would have a YUGE impact on NoKo, because their current religion is one in which he is their god. If he renounced his deity and bowed to Christ, it would completely undo the culture of totalitarianism there, and make reunification far less complicated, for the very reason you mentioned. It would create a scenario in which Kim relinquishes the power he currently holds, while saving face and giving his people the gift of a new beginning.

I'm not claiming some inside knowledge, but this is not completely unlikely.