This piece:

http://www.npr.org/blogs/ed/2014/11/11/356357971/common-core-reading-the-new-colossus

rather neatly exemplifies the promise and problems of detracking as discussed in the now-closed thread. On the one hand, we see an inspiring depiction of a class working with a rather difficult poem and figuring it out--including learners considered "weak." On the other, as the parent of a first grader who is currently reading and writing about a 6th-grade level book in class (thanks to a great teacher), the passages about "unleveling" and making everyone read grade-level text struck cold fear into my heart.