I would personally be interested in 5 reviews, all of which can provide information specific to your visit that many others have not commented on or have not experienced.
World Heritage Sites (3)
Gochang, Hwasun, and Ganghwa Dolmen - Only 1 reviewer mentioned the Hwasun Dolmen site. Of the 3 dolmen clusters, this is the one I have not visited.
Baekje Historic Areas - You are the first reviewer to visit Mireuksaji, after its full re-assembly, thoughts?
Namhansanseong - How much of the wall did you actually hike? Did you go to the ruined outer wall?
Tentative Sites (2)
Southwestern Coast Tidal Flats - No reviewer has mentioned any other site besides Suncheon, what was your impression of the Gochang tidal flats? Being Korea's nomination for 2020, it would be nice to hear more about the other serial components.
Stone Buddhas and Pagodas at Hwasun Unjusa Temple - Currently a topic on the Top Missing List, is this the best cultural site remaining on Korea's Tentative List?