We have a different setup than most I have seen but still it might be interesting to see this option as well.
For us, 8 schools in 1 district, we have all our staff in one OU as a lot of staff work on multiple schools and it wasn't plausible to have the staff get the right OU in time in an automated manner. We have an automated OU structure for our classes through our scheduling software, but just the Students > School was what we had at first.
We had, and partially still have, our directory use the department field set to their class, and we added custom schemas to add their years and school, and class there as well.