From what I have read of this, all they seem to have accomplished is to show the world, and particulary the US, S Korean and Japanese eyes and ears watching carefully, the current limits of their technology and their development process.
Iran seems to be one of the current customers of N Korean missiles, so it should have the mullahs questioning the reliability of the bargain price babies that they have in their missile silos also.
It depends on how their next launch goes, if more succesful, ie it lasts more than 40 seconds or so of flight, then US might consider stepping up the calls for action.
It seems to me better that the N Koreans are showing their limitations, rather than being able to use the uncertainty of their status as a bargaining chip.
From what I have read, it seems to be quite a difficult process to get a nuclear weapon small enough to fit on any sort of long range missile.
It seems that at the present state of development of their missiles, they represent more of a threat to the N Koreans themselves and to those close enough to get damaged by the unintentioned blast at liftoff, than to any distant target.
