Then.......we use air power to just take our time mopping up that huge infantry of theirs. Human wave attacks would be nothing more than suicide in this day and age........and that's all they'd have left.
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.