It's common that capital city becomes the centre of all sorts of culture, but Seoul has gone too far.
Seoul has about threefold more population by comparison with Pusan the second greatest city and has more better welfare, wage and infrastructures than Pusan.
Naturally any cities are not to be even compared to Seoul
This may cause serious problems: extremely expensive house-price, congested road conditions, environmental contamination and others.
Though it's important to increase and maintain the local populations and economy to solve this matter, it's not easy due to the lack of provision of decent works and extension of foundations.
To sum up, that's obvious result of regional imbalance of national land planning. so, Seoul is 'Seoul Republic'.
anyway, if you are seeking better place to visit, Just go to Jeju.