What about student choice
In our state thousands of teachers are going through a masters class called Smart Step Literacy Lab. We focus a lot on Reading and Writing workshops, but one of the big aspects is filling your room with books and giving students access and choice.
I only teach 1 novel as a class, it doesn't make sense to me to teach every child in class a novel that is not on everyone's level, is not a book they would choose or find interesting, etc. I know we all should read books we would not normally choose on our own and be open to new genres and experiences.
That is why my students must complete a genre bingo or some other genre requirement.
I use Literature Circles several days a week and students must also read 6 books a nine weeks on their own.
I have a meeting in 2 weeks about this same subject. I teach 6th grade reading and know sometimes students have read a book in another grade, so either they read the book and get a different perspective or point of veiw from classmates and me, or they are in a group with a different book.
It seems frustrating to me that because someone has created a great lesson on a book in another grade that children who want to read the book before that can be told no.
I guide and steer my children to certain books and encourage them to read within their level, but it is okay to read a lower level book occassionally just as it is okay to read a higher level book occassionally.
The main idea here is that students should have choice in their readings and love to read! No one should tell another teacher that they cannot teach a book that they love and will benefit their children. Some books are classics and students should have access to them, however so many great books come out each year that teachers should be constantly changing their book units to come up with good books that will benefit, encourage and excite their students.

I also believe re-reading a book can be beneficial to students. Several teachers did a unit on Esperanza Rising after it won awards, but honestly 6-8 grade would probably be the best grades to read the book because of the length, the aspects that may be over the heads of younger children etc. So if students read the book in younger grades I will focus on many aspects they probably did not understand in earlier years. Besides if parents and kids research anything about a book they are going to read they can find the same information many teachers are using.