A long essay with a lot to think about. I believe that every subject taught at most levels can incorporate Critical Thinking, and it may not take hours and hours of extra work if it is included for even a few moments daily. Most Reading and English teachers teach Critical Reading in some form; proof from the text, alternate points of view, questioning sources. This type of questioning is possible in History, Math, Science, and just about everything else. Even a megacognitive question: "How do you know what you think you know?" can be asked daily. A teacher can also have plenty of other resources available for students to read and study. It can be done!
Absolute agreement on class size. We're not meant to teach; we're meant to warehouse and babysit. I am a retired first-grade teacher. One year, somehow, I managed to have only 14 students. With the amount of time I had with each student, I could probably have taught them all physics. As you know, however, small class sizes and rigor are what you get in private schools. We don't like to pay for other people's children to get goodies.
Thanks so much for writing.