Could you elaborate a little, what exactly you mean? There certainly was resistance to the speed of reunification or the joining of the new states. Keeping the wall in it's entirety was probably not feasible; that would have meant keeping and paying for about 150 km of border fortifications in and around Berlin and a further 1400 km between FRG and GDR. As this wall was the symbol of oppression and nobody at the time was planning to kill people for crossing between the states (after the revolution had gone of without any shots fired) it didn't really have a chance in the zeitgeist. But the official dismantling didn't start until a new government had been elected democratically in the GDR in the summer of 1990. So which part do you mean reunification, the complete border between the states or the wall in and/or around Berlin?