Not at all comparable. West Germany had almost four times the population of East Germany, & the difference in economic level, education, & exposure to the outside world was much less. North Korea has half the population of the south, & is so much poorer that the difference in living standards is clearly visible in the height difference.
Estimates of East German incomes based on tracking back from post-unification German statistics put them at 47% of the West German level in 1989, but that's probably a slight underestimate, since it didn't take account of the price differences that still existed in the base figures. North Korean income levels are probably somewhere around 10% of South Korean levels, adjusted for price differences.
Most East Germans could & did watch West German television. North Korean TVs are pre-tuned to N. Korea's official channels. East German was easy to visit (I did so, for example) & foreigners could & did wander around freely. W. Germans with relatives in the East could & did visit them freely. E. Germans could visit other E. European countries fairly easily - & millions of them did. N. Koreans can't go anywhere, & the few foreigners who visit are escorted at all times. After retirement, E. Germans could move pretty freely between E & West - the E. German border controls were to stop emigration of workers. Some retired to W. Germany, & went back to visit their children & grandchildren.
E. Germans could buy foreign books & newspapers (though supplies were limited). Never allowed in N. Korea. E. & W. Germany had been separated for 44 years, & travel had been effectively blocked by the Berlin Wall for only 28 years. N. & S. Korea have been thoroughly separated for 68 years.
East Germans had a very good idea of the differences between how they lived & the West German standard of living. They were as well-fed, lived as long, their babies were slightly less likely to die (yes, really), had greater economic security, but had fewer consumer goods & less freedom. And they knew it. Most N. Koreans probably have only a vague idea of what life is really like in the South. I expect that they don't know that they're several cm shorter, on average, die younger, etc.
You see the differences? The integration of Germany was trivially easy compared to the difficulties of integrating Korea. Comparing them only demonstrates what an immense task it would be to unify Korea.