As I said in the other thread: When we practice with Endo sensei we usually practice very few waza. This exactly was the reason I at first didn't like his seminars, actually. Was so different to what I knew until then.
And even when we practice a certain waza, it's not the waza itself, we focus on, but allways some detail that can be found everywhere and doesn't point in the direction of this certain waza, but is important universally. Not easy to describe. But the nameable waza are more kind of "occasion" to study something deeper, than the aim of the study.
Principles behind waza are rarely or not taught in my observation. It is for the student to discover themselves. Even if you teach it this way, the students will not understand if they are not ready to receive. It may also be that the teacher doesn't know how to teach it properly for the students to understand.
Also, the teacher maybe teaching the principles in class, but the student is focusing on something else. It is for the student to discern what the teacher is ACTUALLY teaching. There's always this type of "miscommunication" happening during classes that the gist of the lesson is entirely missed. So you always have to ask yourself "What is he actually teaching?" It's easy to get distracted trying to mimic the technique or criticizing it, like I do myself.