I spent 5 years in a small city in the former East Germany and I am still spending a lot of time there. The "Ostalgie" is especially the nostalgia of full employment and social bonding. People basically say, we went from communism to hard capitalism without the paternalism social democracy West Germany enjoyed. In 1994, 80% of the jobs in the industry were cut with a few emblematic cases of West German companies buying back the companies, removing the hardware, shipping it in China and resuming the production there. It was not a reunification, it was a take-over without respect for the good things in the East. For example everything with respect to employment of women, women/men pay equality, etc. Nowadays, Germany is figuring out that it was not that bad.
I was not able to find a single person saying, please send back the STASI, it was better with.
You must only accept that early 2000, the bubble crashed, the complete economy went out of track and that just 10 years after the reunification. They did not had the time to taste the good working capitalism.