The problem with a war with N. Korea is; first, all of S. Korea and a large portion of Japan (US bases) would be taken out in a first strike from their artillery before anyone knew they wanted to start a fight. Assuming they take the first action. Then you will have a wall of near a million bodies flooding over the border. Troops would then need to be brought it from the States and European stations. The fight would be near what it was the first time. Except now they do have a naval force (unlike the first time) and stronger air force than the 50's. They also have small scale nukes and are insane enough to deploy them all over the battle field. It will not be as easy of a fight as one might think.
Their air force is larger and has some modernish aircraft, but is still a joke. Their pilots are getting like 3-5 hours a month. They're not combat effective.
Their troops... yeah, I'm sorry but I can't feel terror at a million dudes who are built like 13 year olds because of the toll starvation took on them as the grew up.
No matter how you slice it, they're a very poor country. Their logistics would collapse in less than a month.