In addition to Judith's text:

In a good school, two things are present in a balanced way: a general philosophy and room for individual initiatives by teachers.

School management needs to make sure that all teachers agree on matters like:
-there needs to be a safe atmosphere, in which students are treated with respect by teachers and by peers, irrespective of race, religion, gender, sexual orientation, opinion, appearance,...
-school is a place to learn and to grow, if a student is less bright, he or she should not be judged, but be helped to develop themselves in accordance with their possibilities, if for a very bright student standard lessons are easy, appropriate challenges should be provided.
-students are 'seen' with their personal learning styles, interests, abilities.
-academic standards are met.

Within these boundary conditions, teachers should be able to develop their own interests: those who like to play a leading role in developing differentiated lessons should be allowed to experiment in class, those who would like to raise their own academic level by studying  or doing a PhD should be encouraged to do so, those who would like to develop their skills as a counsellor or a school manager should be helped to fulfill such a specialized role. Also in class, if for example one physics teacher wishes to place somewhat more emphasis on modern physics, a second teacher on issues related to physics which are of importance in society and a third teacher is specialized in technical design, this should be possible, as long as all students learn about the core curriculum and as long as students can work on their own preferences as well.