I think we must all be very aware already what the NK government is like. I don't see not being there as a blessing, as that should be the norm; it's more a blight on those unfortunate to be caught up there.
Unless their military opt to take out the regime (instead of taking out their family & neighbours at the order of the regime) then one wonders what would cause change.
An external strike would need to be very fast & effective to take out all the offensive missile sites before they were used. That seems very unlikely to be achieved.
IMO internal power shift is the only obvious solution, and that risks the country simply jumping from the frying pan into the fire.
(That stated, obviously it's all Boris' and Brexit's fault.)