Re: The path to becoming a sensei
A skilled teacher (as opposed to a skilled student) can not only demonstrate and explain the correct way to do a technique, but can also see what mistakes the students are making. In your case (if I understand your post), you saw that your students were doing something wrong and in response you made suggestions on how to correct their footwork and handgrip, but you failed to see that their real problem was failing to move their bodies.
This is something that a new teacher can work on, but I think few teachers (in the martial arts or skiing or baseball) develop this ability to a high degree. Students who are able to attend class frequently have the advantage of hearing the same technique explained differently by various teachers, or even by the same teacher in various classes. Eventually, you or another teacher would focus on moving the body, and a light would (or might) go on in your students' heads.