I visit quite a few schools, mostly ASD specific and Potterspury provide quite a high level of structure in comparison for some. There's always something about preparing young people for the unpredictability of the world outside of education which can be a challenge and probably needs to start in school however I learned quite a bit about written schedules and student specific plans from Potterspury.
There can never be a one size fits all approach, particularly as if you've met one person with Asperger's Syndrome you've met one just one, and like the rest of the world there is a lot of variety.
I'm sorry Chinagirl that this didn't work for your son, and can understand the concerns of the OP who witnessed bad behaviour from staff. There is good and bad in all of us.