I could write a 500 page book over the whole thing and lay out forty-plus problems.....but I'll limit it to just three significant issues:
1. German law, the Constitution itself....says that anyone who asks for asylum into Germany....MUST be given a chance to do so. That means a guy comes to the border and crosses....then asks for asylum....gets the paperwork, and then a cycle will start up.
You take 15,000 people in one month, via this method....it means that your agency running this has to evaluate and reach some conclusion. There are at least a dozen measurements, and each will give you a score or a 'weight'.
While they wait....maybe on up to a year....they are your problem to support. That means food, shelter, and care. You can figure at least 10,000 Euro per person....while in this wait-and-see situation.
Changing the law? It'll never happen.
2. Germany needs migrants and immigrants. The problem is that they can't reach this reality of saying that you need qualified or skilled migrants....meaning that the bulk of people showing up....don't have the skilcraft or degree to make their application 'shine'.
So then you get on the hook of accepting the unqualified guy.....spending tons of money training them, and two years later....they are a skilled heating guy, or roofer. Will he stay? Well....you don't know. Maybe he stays in Germany for six years and then leaves. But you don't know.
3. There is this odd assumption that all migrants or immigrants have the same level of intelligence, maturity, or civilized nature. That might work ok with Greeks and Mexicans. But you come to some folks who see society in a different way, and can be very hostile or threatening when things don't work their way.
Toss in the fact that some arrive in Germany to discover drugs and alcohol in abundance....then discover they have no self-control. The fact that most of the problem-migrants are young males? This has started to be noticed by Germans, and questions being asked. The public doesn't buy the news media stories as they did back in 2015.
As for this all staying page one in terms of turmoil? That's the thing that you tend to notice. There's some element of blame existing but no one can find the magic person to fire and to resolve the situation.