@boomerang,
I had a conversation around "structure" in the classroom just the other day with a mom. She is home schooling her child for this reason - he needs structure or he works and learns best in a structured environment.
As our kids go (or in this case went) to the same school - we both know all the teachers pretty well - there is one teacher at each grade level so you do not get a choice or option for a different teacher. Any way, his mom was saying she was concerned about the teacher her son would be having so she home schooled him. As she had helped out at the school, she went into the classroom while school was in session and saw that the room for this teacher was a bit in disaray (back packs thrown about and such).
I mentioned (as my daughter is older) how this teacher wasn't so organized - she'd plan a test or project on one day - then change her mind - it was almost like you didn't know what to expect next. A very sweet caring teacher, but far from structured, organized and such.
So Mo, sounds like her little boy, he learns better when he knows what to expect, things are organized, and the classroom is orderly.
At least that is my impression of needing structure in the classroom. Just the way some kids learn better. Or I know sometimes knowing what is expected and being able to rely on your test will be Monday at 10:00am can take a lot of stress off of certain children.