Korean War II?

It's THE Asian flashpoint: the UN-imposed border between Nth.and Sth.Korea, a dotted line on a map after a war that never ended. Much more volatile than China's territorial tiff with Taiwan, the Korean War is still being fought nearly 60 years on - socially, psychologically, idealogically, economically... and every now and then, physically.
There've been many clashes over the years between Nth and Sth: border incursions, snipers, fishing boats sunk or confiscated, a naval vessel torpedoed earlier this year. And now this week, just after a pep-talk visit by He-Who-Shall-Be-Obeyed, the Nth.Korean artillery rained down fire on a disputed island. The South responded in kind, nations condemned, the world held its breath...
Living peacefully (albeit nervously) on a disputed island and fishing in its disputed waters is not provocation enough for an hour-long barrage. However, USA and Sth.Korea start playing wargames in that disputed sea today, saying to the North: "Do ya really wanna mess with us?". Now that show of brute strength and solidarity is surely nothing else but provocation. If no response comes from the North over those military exercises, I'd be surprised.
And yet, is there really that much to fear? After all, Nth.Korea had years to target their weaponry. And in one hour of intense fire, they only managed to kill four people and destroy some lightweight construction. I would have expected such a planned attack to have caused near obliteration!
This smells merely like noisy northern sabre-rattling. And knowing full well that USA is bound by agreement to back the South right up to and even into Korean War II, would the North be stupid enough to push things to the brink for the sake of principle?
The answer's probably "yes"...