Its something that's been oft repeated. Everyone is different. When asked to repeat a technique, Osensei replied each technique exist only once. He didn't mean the waza, he meant the way he did it. Each partner comes with their own set of variables, each attack different. For us to do waza perfectly, we need to intuitively adjust to those variables.
Keeping to form will inevitably lead to failure. However, in the process of learning, Form be-gets Function. Practice form to understand the principles behind it and to apply waza. Even entering ki and kokyu is form. I think only awase onwards is formless.
I was just looking over the videos for shihonage again. Empty step, float the hand but extend ki, feet keeping with chushin, center down hand feels light, compress uke's center, don't lift the hand, shear angle in keeping with awase, enter, keep connection, cut center, wrap, keep head position safe. These are just some of the points I can see. Yet, if you understand shihonage, its just control uke's center down up and down again.
Wanting to do something a particular way is a mindset that is trapped by Form. Feeling uke's energy, let the form follow the function of the waza. To reach this however means going through the form countless of times until the feeling is etched within us! At our stage, we shouldn't abandon Form. I think we will know when Form becomes unnecessary at our own time.