The school I work at has done the same thing with social studies and English. The idea is that the higher level kids will bring up the others and the teacher will no longer have the classes that do absolutely nothing and that more students will be motivated to do better because of the higher general standard of the class. My colleagues love it so far. They say that it really has worked in terms of motivating the lower level kids while still allowing the higher kids to do higher level work that they need.
My DS also comments that his current English class moves slow and lacks depth due to full inclusion. The pace and lack of substantive discussion kills the enjoyment that he could otherwise gain from the assigned literature (honors English doesn�t start until next year at his school).
*Full inclusion at ds�s school includes students scoring at the 60th percentile or higher. I can�t imagine a scenario where the true range is represented in the same �honors level� course!
