Well....this is the long version of the answer.
Prior to 2013, Germany had a migration/immigration program. You (the migrant) would be sitting in X-country and get the idea that you'd like to leave....preferring to enter Germany above other options.
So you'd go to the German consulate/embassy....show a legit ID, and fill out around 15-odd pages to explain your situation. You'd detail what you have to offer (language ability or certificates). The form would be mailed to a 700-odd person agency in Nuremburg.
This agency had a priority written....detailing the plus-points to you getting approved. No one talks about how things worked in the 1960s, 1970s, or 1980s.
This review typically took about six to twelve weeks. Then it'd come back, and you'd get a call to come to pick up your approval 'slip'. At the consulate, they'd ask if you need financial help for the flight. The West Germans (at that time) were nice enough to cover all of this. You'd fly into Frankfurt....spend a few days at some regional facility, and then progress to the town chosen for your new 'life'.
This was pretty simple and business-like. Some people were approved....some people were never approved (maybe having submitted several applications).
So we get to 2013, and here....the dynamics change in a funny way.
The Merkel-coalition is standing there at the beginning of the Iraq-Syria civil war with ISIS....with the belief that there aren't that many coming.
For 2013, I'd guess that the number of people just walking up through Turkey, Greece, Macedonia, Serbia, Hungary, Austria....probably to be no more than 5k to 8k. The fact that none of these countries blocked the borders? The fact that literally none of the 'walkers' wanted to establish themselves in any of these countries? Yeah, this would be brought up and discussed, but no one could grasp that end of the discussion.
BAMF, the agency in Nuremburg had three issues. First, they were built and manned to handle x-number of applications per month. By the end of 2014, they were probably handling three to five times that number. Bringing in more manpower (at least in their mindset) meant training those people and it'd take a long period to achieve this. Second, the top level of the Merkel coalition felt there were way too many disapprovals going on....not realizing that the BAMF folks had the same 'chart' that had existed in the 1970s/1980s for processing people. Third, in the mix of Iraqi/Syrians....there were various other refugees (Afghans, Tunisians, Africans, etc) who'd figured out the route, and they didn't really fit into the approval process.
Eventually, the 'boss' of BAMF would be talked into retirement, and a 'results-orientated' guy would be brought in. Some anger and bitterness existed within the crew, but they were forced to modernize. A business-consulting company gave an evaluation, which probably didn't help matters within the agency. The problem of disapprovals still flowing? Yeah.....that became obvious that if you didn't fit into the agreed-upon matrix....you weren't going to get a visa.
Then you came to two obvious groups which were creating their own stumbling blocks. Politically....this became a happy-thing within various political parties. You could attach the 'good-German' logo to yourself....if you were pro-asylum. Adding to this....the second group....the public news media...became a pro-asylum tool.
As you might imagine, this led to AfD (the party) being taken over and rebranded as the anti-asylum party. Generally, you might not have approved of AfD's leadership or dynamics....but if you were negative about the government handling of migrants/refugees....you voted AfD to 'send' a message.
At the end of 2014, around 450,000 were assembled in Germany and it was a daily topic on the news for the last quarter of the year. At the end of 2015, the number for the year was figured to be in the 950,000 range.
From personal observations, I'd say toward the last half of 2015....this was a political mess that needed fixing.
The general attitude within the leadership? You needed the EU to fix this by taking all of the incoming refugees, and bundling them off to various countries....using a formula that Germany used for the sixteen states. Several EU members were willing to discuss the matter....while several were not thrilled over this idea (refusing to discuss). The Germans figured that you'd just tell the guy who'd walked 1,200 miles....that the guy would get a bunk for a week, and then be shipped off to Italy or Spain. In their mind, he'd accept the EU ordering you to be dispersed.
What fell into place in 2016? Fences. Across the southern border to Greece....came fences and border protection. Suddenly, the number dropped. This wasn't a German idea....it was a realization by the southern states that one single country putting up a border....would trigger migrants passing through to be stuck and these countries really didn't want the situation of caring for asylum seekers.
Since 2016? The number of 250,000 applications per year is mostly normal (this was the normal number prior to 2013, if you were curious.
Yes, there are still migrants walking in, or arriving via boats in Italy.
Presently? The Green Party has attached itself to a serious pro-asylum position, and in recent weeks.....the EU has brought out a fairly tough asylum policy, which the typical Green voter isn't happy about.
Adding to the present problems....the Ukrainian conflict has brought around 1-million folks (mostly women and children) into Germany. Almost none of them have asked for asylum....they just want a period of time for safety reasons to reside in Germany.
Housing and lack of funding? Yeah, these are now brought up almost monthly. The sixteen states say they aren't getting enough funding to handle the situation. Then you have in virtually major city of Germany....a affordable housing crisis.
If you asked me to rank the situation to 2014/2015....no, it's just not that bad. But it probably ranks as a top-five issue politically, and the AfD Party is still maintaining a front on it being a crisis, which probably 10-to-20 percent of the public readily agrees with.
Coming to some rational middle-of-the-road resolution....which would dismantle AfD's discussions? You would think after a while....some general policy would be created and you could finally downsize this discussion (with lesser voter support of AfD). But this hasn't occurred.
Then the final keynote.....the birth-rate is still around 1.4 kids per couple....meaning the population trend line for Germany, over the next generation....is pretty crappy. So they need migrants in some way....to keep the present population of 84-million possible. That's the bitter side-story to consider.