A correction may happen if they take action but traders are not going to sit down and just accept that, and then they are going to move their money to Japan markets, if South Korea does ban bitcoin trading they are going to regret in the future when exchanges begin to pay a lot of taxes.
South Korea will always be a contributing factor to Bitcoin's growth, so that will not change even when they 'change' things up a bit. Great thing is that current growth is coming from all over the world, and for that reason isn't centered in just one country like how things were when China was a big deal. It should result in a more evenly distributed growth that won't get impacted much if one aspect doesn't want to cooperate, or even withdraws itself from the market. This is what we all have been waiting for, and it finally starts getting shape, which is something we can be proud of, especially if you look back at where we have started.