In fact all tests, not only the German or english ones are among other things rated by spelling and style. It makes some sense when you see the school as a preperation for University, where you have to preseent papers as well. Sounds like the German system. If you fail in more than 2 subjects, you go back a class. Same goes for Abitur or Mittlere Reife, but you are allowed only one subject.
Remedial work is voluntary.
The problems of minorities play a smaller role in German school policies. Germany had a massive influx of immigrants over the last two decades, and we are just learning to cope with the problems in education they brought with them. My children will probably have to take an Abitur that is not so different from mine. The questions in German Abitur tend to be quite short either, see examples below, but you have to write your own answers. This allowes the teacher some leeway in interpreting your answers.