Generally, in Berlin at least, it's a mixed bag of complete rebuilt in the old style or new. I'm not sure of the thinking behind the palace you highlight but I did not agree with it. For example the Bundestag had the cupola rebuilt by Sir Norman Foster in a modern style.They seem to be a lot more comfortable with rebuilding something that looks exactly the same in Europe. A lot of town and city centres that look historic have actually been flattened and rebuilt.
This building in Berlin is a total joke (although I'm sure some people think it's lovely):
Berlin Palace - Wikipedia
en.m.wikipedia.org
Another really good example is Gehard Richter's stained glass window in the Koln Dom. His reasoning for the modern approach is interesting.