One last observation before I switch to the one-post-a-week policy. Let's say Germany grants some form of legal residency status to millions of refugees from Syria, Iraq, and Afghanistan.
This is quite the decent thing to do. However, the mere fact that these people are fleeing conflict does not automatically make them good fits for German society. Now many, perhaps most Syrian refugees are from the educated middle classes (they have savings they use to pay for tickets and smugglers) and are relatively progressive, by Middle East standards. Their women don't wear headscarves and are eager for education.
They'll fit right in, no problem.
However, some fraction of the refugees are going to be conservative Muslims. A smaller portion of them will be extremely conservative Muslims. Some may even be Salafists. They will be grateful to Germany for giving them refuge, but they will not change their fundamental beliefs, because that's not how humans work.
Consider, for example, the al-Nusra Front. It's a Syrian Sunni Jihadist group with links to Al-Qaeda. It's not the most radical opposition militia in Syria, that dubious honor belongs to ISIS, which considers al-Nusra to be too soft. Al-Nusra has carried out suicide bombings, and is considered a terrorist organization by about 10 foreign governments, including France and Turkey. It's also by most accounts the strongest component of the anti-government Syrian opposition. According to Wikipedia, al-Nusra is a "formidable force with strong popular support in Syria".
It's hardly far-fetched to supposed that thousands of those strong popular supporters have already fled and may flee in the future if their territory is taken over by government forces or ISIS. Once they reach Germany, what are their opinions going to be about gays? About women wearing headscarves? About pop music? About multiparty secular democracy? About swimming lessons for girls? About religious education? About cartoons mocking Mohammed?
About -- ahem, cough cough -- German policy toward Israel? (remember that Palestinian refugee girl who cried during a town meeting with Angela Merkel and then said in a follow-up interview that Israel shouldn't exist?)
Germany's record on assimilating conservative Muslims (or, if you prefer, the record conservative Muslims in Germany have in integrating into German society) is mixed, to say the least. According to a recent study (g), 60% of European Muslims would not befriend a homosexual, and 45% say Jews cannot be trusted. I wonder if a fresh influx of 100,000? 200,000? 300,000? is going to make things easier?