A case could be made that this state-level independence is a strength, not a flaw: you can experiment and see what works and doesn't, and also accommodate to lo

A case could be made that this state-level independence is a strength, not a flaw: you can experiment and see what works and doesn't, and also accommodate to local realities if needed. In practice, I agree with you, states are not doing a good job and we don't see tangible benefits from all this variety. To be pedantic, this disjointed system IS the German educational system. And I would worry about fixing it before putting the blame on immigrants.