We've been given quite a bit of info regarding Korea since the episode: Steven's Dream. More so than Empire City, yet even that has its own page. So, should Korea be given it's own page? If so, maybe something similar to the Beach City and Empire City pages?
Korea is a pretty insignificant location in the show to be granted its own page. As far as I know, Korea isn't seen or mentioned outside of the episode you listed, whereas Beach City and Empire City are both significant and reoccuring locations respectively.
Weakly support: It could possibly have its own section of the Earth page. Sorta like how there's a section of the Minor Locations page for various small-scale locations and businesses and stuff, the Earth page could have a section on large-scale Locations on Earth that are seen or mentioned like Korea, Kansas, Bulgaria, etc.