How did you learn techniques (waza, kaeshi-waza, whatever) in the first place? According to the posts all training is just about finding openings on which you often will not act.
No, I was specifically answering a specific question. Please try not to read more into my words than I've written.
Of course I learn in class, working with a partner, like everybody else.
The question had to do with changes/reversals.
My answer was intended to say that I do not believe that one has to learn how to do them via rote practice of "this fails so look FOR THAT".
In my experience, if you have your basics down to some degree, that when it comes to changes from one to another or to reversals, it should be possible to find what is there via slow partner practice rather than rely on learning a rote sequence, which to me is the antithesis of aikido.
My two cents.