The primary concern is the use of artillery and multi barrel rocket launchers devastating any ROK ground forces. Russia demonstrated their long distance lethality in Ukraine.
I'm also curious at the quality of DPRKs SAMs. The new S400 ones definitely pose a problem even for modern American planes. I've heard even the 90s model S300 could still be a serious concern.
I remember hearing the War Nerd talk about a couple of war hawks who wrote a series of articles about intervention in Syria totally glossing over the real threat they pose. And these guys apparently had a lot of influence in Washington among the establishment neocons and Clinton types. These SAMs are apparently very underrated. We just assume America has the best tech but real world combat is quite different.
South Korea has plenty of artillery and MLRS to counter N Korean threats, not to mention counter-battery radar systems.
I read someone who quoted a South Korean army officer who said once S Korean K9 SPH started rolling off the factory, South Korean army gained the advantage over N Korean army.
And with my very amateur level knowledge, I agree.
I'm not disparaging what Colonel Dani was able to accomplish using outdated equipment, but it's important to note how little the Yugoslavian air defense was able to achieve as a whole.
So the DPRK would need to achieve total surprise, fight ~20 miles to Seoul against an opponent who is equipped with mostly modern weapons, and who has planned for this very attack. They also need to do this with no air support, little to no armored support, and limited night fighting capabilities.