Stratfor's undoubtedly correct analysis of the NK artillery capacity within range of Seoul is the reason that any attack on NK has to begin with a tactical nuclear equivalent of carpet bombing of all NK military positions within artillery range fo Seoul, and all NK missile emplacements. (On top of the usual measures to gain air supremacy.)
(Heck, even my wife, who is usually almost pacifist and suffers from a mild case of BDS was advocating nuclear first strike against NK when they were running missile tests, so there might be enough political support for it in the US. Trouble is, SK has to be in, or its a non-starter.)
I do not believe tac nukes are required to attack the north for two reasons:
1. As soon as North Korea launches an artillery shell, it betrays the exact (and I do mean exact) coordinates of the launch position. And the NKs big cannons are not mobile, like SCUD missiles.
2. JDAMS love exact coordinates. So does our artillery.
I don't believe NK will have nuclear capable artillery shells for some time. Unfortunately, they no doubt have plenty of nasty chemical shells.
They will have to make their first volley a good one. Because that is all they will get.
The SCUDs are a much more dangerous threat. NK would be better off using an Iraq SCUD strategy (shoot and scoot) rather than artillery (shoot and die). Artillery is obsolete as a multiple use weapon against the U.S. Just ask the Iraqis on the Kuwait border who were stupid enough to fire on us.