I don't like the saying function over form, if a very thorough commentary isn't attached to it. The problem is that the relation "over" can be interpreted in a few ways. It can for example mean "is more important than", for example "function is more important than form". It can also mean "is based on / arises from", for example "Function arises from form."
It doesn't matter that much which art we are talking about, but form and function are always in a symbiosis, so it could be argued that form is some kind of an efficient abstract entity containing a lot of stuff that has a function. Form is taught through function (if a technique has a flaw, the correction is based on function) and function is taught through form (the content of these kinds of curricula is stored in forms, katas).
Could even be argued that shu-ha-ri is a process of going from "function over form" to "form over function", as long as the relation "over" means "arises from". In the beginning a correct form has to be established and then in the process function becomes clearer and even the form improves. Even if this obviosly has the element of a feedback-loop and in one way could be interpreted as "form over function", establishing the form and teaching through it is the point. But then later when the teachings are understood and gotten, different approaches could be considered. Then either constructing a new form or staying with the old is based on function and the form can in a whole new way be respected for how well it can be used as a vehicle to get the job done, even if, at least in principle, now the teacher could construct a new form or a system of forms to teach the same stuff.
But I think in Wado the form and the function must live in a symbiosis. The form is what is central and the function is what we train the form for and also a feedback-mechanism for learning the form better. "Central" doesn't mean more important. It just means that it's what every wadoka share and what is on the menu.
I guess Gary agrees with a lot of this stuff, right? And I can very well imagine, someone thinking exactly like me could reverse every "form over function" and vice versa in this post. I have never experienced someone saying one of these two either way and not thought "on the other hand..." and I really think the symbiosis-viewpoint could help.
But how did Gary intend this to relate to the conversation above? And did you mean by your example from Niten Ichi-ryu something that could be compared to trying to hit within the correct form in for example kihon kumite? Or did you mean some kind of half-free, half-pre-arranged training form? Also, what did you mean by the process of form first through solo kata and the realising this in kata-geiko? I mean, what does "kata-geiko" refer to in this context? Pairwork or a study in general? Because I also think in Wado we often arrive to a more correct form through keiko...