http://teacherleaders.typepad.com/the_tempered_radical/

In the US, it's tough for teachers to have a lot of doing when so much of the time is dedicated to preparing kids for the assessment tests. I don't think there's any problem being very demanding when it comes to the 'knowing' part about education, but exercises that reinforce the material or give it context are pretty essential. The successful kids get this on their own time.

Class sizes, class sizes...