It's a terrifying prospect.
Essentially even as nutty as they are... one would hope even Kim Jong Un and his miniors would recognize the limited capability they truly have.
Alot of projections put their strike strategy at crashing the border with large scale tank and infantry pushes that'll be quickly crushed by air power.
The only thing that's of true concern is the following.
1) Artillery aimed at Seoul, regardless of how efficient air power is, it's going to take time to take down those batteries, meanwhile alot of people are going to die.
2) and most important of all, North Korea is alleged to have about 200, 000 special forces.
Intelligence suggests that in the event of a war these 200, 000 would infiltrate the ROK via small boats, tunnels and air.
They are alleged to have ROK uniforms and will than dedicate themselves to causing the most havoc possible, attacking air bases, hospitals, schools, grocery stores, government buildings and just generally ****ing up the entire back line.
(2) is of most concern. Every credible strategy and policy paper brings up this issue as the biggest reason why in the beginning of hostilities the North could cause real issues and may even initially gain serious ground.