Correlation of Forces, North vs South Korea

In a nutshell, the Norks have twice the force of the south.  Saturday's Wall St Journal gives a breakdown, based upon a South Korean Defense White Paper of 2016.  The South has 655,000 regular troops (including a mere 20,000 American troops) against the North's 1.28 million troops.  As backup, the South has 3.1 million reserve troops but the North has 7.62 million.   Which gives the NORKs twice the number of soldiers as the South.  And, these force levels are enormous.  Consider that Hitler only had 2.5 million soldiers in the army that he sent to attack the Soviet Union in 1941.   And Nazi Germany was a much bigger country, fully mobilized for war, supported by a population about three times the size of North Korea.   In short, both Korea's have really really big armies, and a war between them would be bad.   Notice also that our troops in Korea are dwarfed by the South Korean forces.   Note that our 20,000 troops is twenty times the size of the force we moved into the Baltic states a few months ago  amid much fanfare in the MSM. 
    The article goes on to give numbers of warplanes, helicopters, tanks, armored personnel carriers, conventional artillery, rocket artillery, missiles, warships, and submarines.  All the quantities are impressive.  For instance the North is credited with 4300 tanks.   Rommel at his best never had more than 400 tanks.   The North is believed to have 70 submarines,  which is twice what  Admiral Donitz  had in 1940.  Granted these are diesel electric subs which lack the speed and range of nuclear subs, but are every bit as deadly when they get within torpedo range.  
   Another interesting but scary fact.  The North has 5500 rocket artillery pieces against a mere 240 in the South.  These weapons are descendants of the old Soviet Katyusha rockets of WWII.  They fufill the same role as conventional artillery.   The rocket launchers are cheaper and lighter, and have somewhat better range, and throw heavier projectiles than conventional artillery, at a sacrifice of accuracy.  If you are bombarding Seoul  rocket artillery is plenty accurate enough.   Presumably a lot of those 5500 pieces are dug in around Seoul, waiting for the word to open fire.   Cleaning them out with counter battery fire and air strikes will take forever.   Especially as the fire finder radars only work on unpowered artillery and mortar shells.  Rockets keep accelerating, the radar has no idea how long they have been under acceleration when they first detect them and they cannot compute the launch site for attention by our own artillery.
  In short, both sides have very large forces,  forces the size of WWII forces, ready for combat.  Starting up the Korean war again promises to be really bloody.  The Journal's commentary explains that the South Koreans are expected to win thru better training, better equipment and high morale, even when outnumbered 2:1.    But it won't be easy.