Something drastic needs to happen prior to NK getting all of their ducks in a row. If too much time passes, then even if we attempt a pre-emptive strike they will have enough time to respond in the manner they are threatening.
If this thing is being "gamed" (and we know it is), then the goal is to acquire resolution without fallout (in every sense of that term). Maybe there are other routes, but it seems that only something that catches them completely off-guard will be successful in preventing them from taking a very nasty pot shot at their neighbors as they are going down.
1- We don't know where the actual nuclear weapons are being stored, produced, or developed. Given the fact that the NKs have moved their entire military infrastructure underground, it is unreasonable to assume that they would leave their most critical defense component totally exposed at a site that appears regulary on CNN.
2 - It forces their hand. Kim has two options, certain political collapse, or retaliation.
I'm all for keeping NKs feet a roasting, but we need a better end strategy before we stir up the hornets nest.