for DECADES accredited colleges of teacher education have emphasized high standards and clinical training with hands-ons experience. It was state governments who don't want to PAY for clinical internships, demonstration schools, teachers colleges, and supervising professors.
This is a no-brainer. Every teacher accrediting agency for as long as a century have put clinical standards in the curriculum. Right now, there is probably too little "theory" at this point to go with the hands-on experience. Teachers don't have enough coursework in very important topics like: testing , new curriculums that are NOT developmentally appropriate (Common Core), diagnosing special kids, school law, and ESOL (should teachers be bilingual?). You have to learn material and also put it into practice. It can be pretty complicated to make the connection, and guided experience is the only real "test".
There is simply no time in most college degrees for modern teachers to learn how to deal with the subject they teach, all the different kinds of kids, legal issues, and high-stakes assessment. In fact, even with a Masters many teachers are surprised by new things all the time.
OTOH, district training is sometimes political and not useful but this varies. Universities have difficulty hiring and keeping good faculty because they also have budget cuts that often target professional schools. Clinical experience supervised by veteran teachers is EXPENSIVE - just like you want doctors and lawyers to learn from professors who know what they are doing - but states don't want to pay for it.
Teacher certifications tests have been around since my first days of teaching. My wife and I have taken them and passed them in multiple subjects in multiple states. The teacher certifications tests are almost worthless compared to graduating from a good teacher training programs where you are learning from experienced supervising teachers and professors. If you don't pass that experience, you probably are not ready to be a teacher even if you pass a certification test. Short cuts and tests are simply no substitute for a year or two of guided practice.
Been there!!