I think that the idea of a flipped classroom is a great thought, but in order for it to work effectively and benefit your students, it puts a lot of trust and reliance on the students. Having students participate in the lesson outside of class and then using class time for activities and observation is a great way to maximize learning and practice with the L2 for ELL students. Students however, must be motivated and must be accountable for actually participating in the lesson prior to getting in the classroom. I think with older learners that teachers would have better luck in being able to count on their students to participate, but teachers might have some issues with younger learners. Younger learners might need the assistance of their parents to access the lessons, but some parents may not be as involved as others. These are some things that teachers must consider before implementing this learning technique. Teachers must also make sure that all students have access to view the lesson outside of class before using the strategy of flipped classrooms.
In theory, I think that "flipped classrooms" are very interesting and innovative strategy that could really help ESL students. However, there is a lot that needs to happen to ensure that this style of teaching/learning can work smoothly. With the right class and the right resources, this tool could maximize learning and potential for all students.