It has huge problems with its exports. Roughly half of its GDP comes from export. And since the 2008 financial crisis that hit other exporting countries so hard, Germany only grew its exports. How's that possible? They started to export more to the UK, Canada and the US. But it seems they are reaching their limit and if the cyclical crisis comes to the US it will really hurt Germany. When half of the country's GDP comes from export, a 10% drop in export leads to 5% drop in GDP.
It also has a banking system, a refugee and rising nationalism problem.
> ... won't get much criticism.
It won't, in Germany. It will in recipients countries.
> ... why Germany has the power it has
Half of Germany's wealth comes from its export. It means it comes from its clients. Germany's economy is dependent on other countries buying their goods. Anything that threatens the free movement of goods is a threat to Germany's well being. Let say, if some country decides to leave the common market and establish trade barriers to protect its national market and then it does well on its own, other countries that currently struggle may follow the suit and protect their producers by blocking German goods. It would be a disaster for Germany.