I thought it was a good idea to switch up the classes for the kaiwa, but there are also a few disadvantages. I think it's good to practice with different people, and not just the ones that you are comfortable with, but also that this takes more of the class time to do the same thing. If this were something we did every kaiwa day, that might not continue to be a problem, as we would develop better skills for listening to different styles of speech. I personally thought it was a very interesting idea and a worthwhile experience.