Unfortunately, as I see it, there is too much at stake to attack NK.
Seoul could suffer millions of deaths; Japan could also suffer huge losses and anyone in the region would be severely affected. China would face a massive onslaught of refo's crossing their border. And that would all be possible under a conventional weapons war scenario.
NK doesn't need a missile to deliver nukes. Bung 'em on a plane, fly over to Seoul on a suicide mission and even if the plane was shot down 10kms from Seoul, kaboom, end of population of Seoul. Also, fall out would probably kill many in NK. But that would bother Kim as he only thinks of him and his dynasty.
I think, as much as I would like to take out Kim and his generals in a pre-emptive strike, the risks associated are too great.
China is the great hope that a sensible negotiated agreement can be consummated between the West and the idiot Kim.