Well, it was already destroyed by conventional bombing. In fact, while the Soviets were busy surrounding the city, the Allies leveled in the inner city and the Soviets did not have a problem with it. Actually, nuking it would be a waste, as there was no proper way to assess the damage. That is why Nagasaki and Hiroshima were selected, as they were not bombed and the damage could be assessed. There is little chance of Germany being nuked, as most cities were already rubble with fewer people, and there was no point in blowing up what was going to be overrun in days, weeks, or months. I doubt there would be a need to do a tactical bombing either, as the Germans were ready to surrender and the Brass wanted to do a real field test to get it ready for the NEXT war.
Besides, the main reason it worked so well in the two historical examples was the large number of wooden and paper buildings in Japan. Concrete, brick and steel held up much better, so it won't have nearly as dramatic an effect on German cities, as they were of these materials. It would still effect the populations left in the cities, but they will be shielded better by the structures in their cities and by being in basements. That is until the radiation starts kicking in, which will kill many in the coming days and months. In fact, the death totals in the Japanese bombings don't include the radiation fatalities which were worse than the initial losses. That is going to have an effect on the German mindset after the war, which will probably give some reason to feel that they were victims of allied atrocities. Plus, being a western country, the radiation fallout (in both senses of the word) would be better documented and portrayed in the US than the Japanese casualties.