I was travelling around Germany a few years after reunification. The people I was with, late teen, early 20's, leftish leaning, Germans from the west, were complaining about the costs of the reunification, saying tjat if they'd been given accurate information, they might have voted against it.
When we went to Bautzen, there was a lot of resentment of West Germans just ciming in, buying anything they liked and treating the East like a giant theme park.
That was around 1995. By then though it was a done deal.
I think if the financial cost had been known, the social effects known, it might have been delayed a few years while the East brought itself up to a nearer standard.