The South Korean watchdog agency (Board of Audit and Inspection, or BAI) recently issued a report recommending that 25 senior defense officials be disciplined for lapses in judgment and performance leading up to and following the sinking (by a North Korean submarine) of the corvette Cheonan last March. The charges include not increasing readiness after a naval skirmish with North Korean gunboats last November (which included the sinking of a North Korean gunboat), and ignoring the problems with anti-submarine capabilities in coastal waters. This has been a long term problem, even though most North Korean submarines are miniature coastal types.
In the 1990s, one of these boats ran ashore in South Korea, while landing spies. One of the crewmen was captured and debriefed (and is now living as a refugee in South Korea), providing South Korea with considerable knowledge about North Korean coastal submarine operations. This did not lead to any meaningful effort to improve South Korea's ability to deal with these small subs. Instead, the South Korean Navy switched its efforts to developing a high seas fleet, ignoring the more immediate coastal threat from North Korean subs and commandos.
The BAI also criticized how ineptly the military responded to the sinking of the Cheonan, and implied that there were systemic problems in the South Korean military command that crippled combat effectiveness. American military commanders have long made some of the same complaints, but quietly so as not to cause a diplomatic uproar. Unless the BAI report is quickly swept under the rug, there could be some major changes in the leadership, and practices, of the South Korean armed forces.