Any military strike against NK, no matter how quickly or massively, would still be damaging (at a minimum) to Seoul and other SK cities even without a "ground" war. There would also be damage done to Japan. The damage would be devastating to their economies...and thus to the world economy (not to mention cost in lives).
Even with antiquated & reliability issues factored in, the massive numbers of missiles and long (enough) range artillery are of great concern.
The 2nd Korean war would make Desert Storm I look like a moderate training exercise. This all assumes that China and/or Russia remain on the sideline as well. A major, major if.
"What Would the Second Korean War Look Like?What Would the Second Korean War Look Like?
The first 24 hours of war on the Korean peninsula could cost hundreds of thousands of lives.
By Franz-Stefan Gady - April 19, 2017...One explanation for this may be that estimates of casualties and physical destruction on the Korean Peninsula (and possibly Japan) under any war scenario are so exceedingly high. Should Pyongyang live up to its threat of turning Seoul into a “sea of fire,” casualties in the larger Seoul metropolitan area alone may surpass 100,000 within 48 hours, according to some estimates, even without the use of North Korean weapons of mass destruction. The U.S. Department of Defense assessed that a Second Korean War could produce 200,000-300,000 South Korean and U.S. military casualties within the first 90 days, in addition to hundreds of thousands of civilian deaths.
..."
Part 4: How North Korea Would Retaliate
How much damage could North Korea unleash even without nuclear weapons?
How North Korea Could Kill Millions of People
If there was no threat of a nuclear retaliation or ICBM attack, they could be isolated and ignored. But that genie is darn near out of the bottle...if not already.
We can "thank" the Clintons as well as every other president since him for doing everything from very little to actually assisting that insane regime for this damned treacherous situation we...and the area, find ourselves in.
All of the scenarios you posted links to assume the worst case scenario, and near incompetence by the US and South Korea.
And it assumes the NORKS attack first.
All that fancy pants artillery would be taken out in 24hrs or less if it is in range of Seoul, and within 72hrs deeper in.
Strategic Bombers carrying cluster bombs would ensure that.