I went back to school in my forties to get certified to teach and was very surprised at the quality of my education classes. There was some junk, but most of it was surprisingly solid. A thorough background is very definitely needed in the subject discpline and I was fortunate enough to go to a school that had higher requirements for its ed majors than its regular majors (English). But I have learned a lot from the ed courses.
My husband decided in college that he wanted to teach college. While he taught in grad school, he did a terrible job teaching, thinking subject matter was all he needed. Students complained and his adviser discussed it with him. When he realized that he wanted to teach, he enrolled him in ed courses even though he was enrolled in a research-oriented Ph.D. curriculum. Even today, he credits his ed courses for helping him be a good teacher.
I am absolutely convinced 1 does not need to waste 4 solid years doing "education" education when it can most assuredly be done at best as a minor in undergrad.
I am an attorney with the Government. I have a specialty related to Business, and have taught Graduate Business Courses at night a University. My teaching experience came from the military (I was an Army Reservist that taught military courses). The military has some excellent courses on how to teach.
Teaching Grad Students was great. Out of about 120 students in 5 years, I only had a handful (3-4) that did poorly. Many aced the exams, consistently went to class and worked a full time job, most had children (small).
The key to teaching, in my opinion, is making the students a part of the teaching experience. Lecturing a group of students is not as effective. It helps to try to understand where they are coming from and try to make the subject meaningful for them.
My Son and others that have taught have little respect for the ED classes they took in college.
I am thinking of teaching History in HS after I retire, but I hate the thought of having to take ED courses.