Even if I'm not entirely sold on the notion of creating "Invisibles" all year long, Ben Slavic's book is full of great insight and practical plans for implementing a student-centered CI-based classroom. In particular, I appreciated his insistence on the need for stern classroom management, since I've heard many teachers in "communication-based" classrooms complain about disengagement and downright bad behavior from the students. It's incredibly valuable to hear from a veteran teacher who knows the research about what works and what doesn't, what creates the most joy, engagement, and acquisition, and what is just a waste of time.
Addendum: As a Latin teacher, one deficiency I see with this approach -- or rather, we might say something that needs to be supplemented -- is the language classroom's capacity to be an encounter with the target culture. Many students who come to Latin classes do so precisely because of their interest in history, culture, and especially mythology. So, I can co-create stories with them that feature such myths or characters set in the culture of the Greco-Roman world, which, I believe, is another way to engage their interest.