Unless we have specific intelligence, are you willing to gamble with the lives of many and the world econcomy? I agree that if we can destory their launch capabilities, then NK would order its army to invade South Korea. A better scenario but still a very messy war. You then have to worry whether China may assist NK. The entire region could spiral out of control.
We don't have many good options right now regarding NK.
Keep your day job, by the way.
Destroy the launch facilities, destroy air fields. And if the infantry moves an inch, tac nukes along the line.
That's the only way to keep Seoul intact, and prevent NK from using nukes.