Standardizing the curriculuum is also NOT the answer. Offering MORE choices is. We've been lucky enough to have sent both of our kids to very child friendly private schools, my youngest has since left and gone on to public school. And so far we've been very pleased with her progress there as well.
"Unlike most european nations, we do not have a homogenous population in many states and cities"
And what countries would these be? The days of a Europe with a "homogeneous population" are long ago, assuming that this is in any way relevant. Most EU countries, including UK, France, Spain, Italy, and Germany have many, many African and Muslim inhabitants.