Director changes have been handled very well at least on the short run, in recent years. Many bigger schools with director changes keep the same methods throughout the first year and ease into the new head director's methodology, for better or worse, so I expect these schools to either remain in their spots or some bump up a lot.
I'd expect nearly no movement unless one of the new directors comes in and ruins the band experience for people or is just the goat of managing a band I expect not much improvement or failure from those bands which could leave the door open for those bands that aren't going through change.