I can’t imagine they would attempt anything like this unless China was on board. I wonder what they would have to promise China for its acquiescence.
South Korea would have to provide the on-the-ground muscle. Are they ready to take this on? And this would have to be real shock-and-awe blitzkrieg warfare, because otherwise Seoul is right in the cross-hairs.
This all seems far-fetched to me. More likely they start to apply pressure and some previously no-name general mounts a coup.
South Korea is less worried about the war than it is about the aftermath. Integrating East Germany set Germany back about a decade economically because of the disparity between the two regions.
The difference between DPRK and ROK is greater by an order of magnitude. You’d need to have a twenty-year transition with civic education and internal passports before you could even allow north koreans to vote in korean elections.
The DMZ would remain up as a control against internal migration.
I think everyone’s preferred outcome is a coup in DPRK that results in a gradual transition.