It is correct that not many Western tourists come here. Most of the tourists are from Japan and China, as well as a handful from other Asian countries. For most of these tourists, it's a shopping trip and for things like K-Pop and K-Dramas (concerts, going to places made famous in dramas, studio tours etc.).
We have done that (American married to a Japanese), but we also enjoy the food and culture. We have been to Korea perhaps 12 times over the last 16 years.
Western tourists skip over it because other countries in Asia have better food, better scenery, a friendlier outward appearance (smiling Thais, for example), better architecture, a rougher feel etc.
Hmm, better food? I would say Korean food uses a lot of vegetables and in some ways it is a lot more like interesting than Japanese (which tends to be blander). There is also some great scenery in some areas, Cheju for instance.
If I were a tourist, I would not come back here. The downside of Korea is the serious lack of diversity. This is a country that prides itself on homogeneity (read: lack of diversity). I'm not making this up; this literally is a point of pride to many Koreans. Koreans, by and large, view themselves as pure and homogenous.
Japan is similar in that sense. I haven't ever felt bored returning to Korea, though some of our past trips were also stop overs for 2-3 days on our way to Europe.
There's a great level of sameness to the cities. The same boring, borderline-Soviet architecture. Sometimes cities will have cool little areas, but there's not the range in character in cities that you'd find in a lot of other countries.
Tokyo especially has been accused of the same problem. I think both cities (Seoul and Tokyo) have exceptions in certain areas. Throughout both countries there are interesting traditional buildings as well.
The same is true for the food. It's true that there's nothing like Korean food. And it can be tasty. But it seriously lacks diversity and innovation; so much of it is smothered in pepper flakes, pepper paste, garlic and sesame.
Have to politely disagree here. Depends on the dishes, though granted kimchi does feature in a lot of the dishes. Japan likewise uses a lot of dashi.
It lacks outstanding freshness (even if the ingredients are fresh; they're hidden by the seasoning, not enhanced by it.
Again, disagree. Depends on the area. Have you traveled to many areas in S. Korea?
Most Koreans I've encountered truly believe Korean food is the most delicious in the world and that it is inherently better than other cuisines,despite little to no exposure to other cuisines. Frankly, it's viewed as better because it is Korean. Thus, you get something that is unique,but there is no urge to innovate and improve.
You get this same opinion expressed by some Japanese, though some do have some exposure to other cuisines, but this may be Japanese versions of other cuisines (in other words, they have mostly sampled other cuisines in Japan).
My recommendation: I would go check it out, it definitely has places of interest. Reasonably priced too and fairly easy to get around.