Erick Mead wrote:
The regimented model would seem to require some other measure of design or plan to accomplish that, also by its nature.
The other measure required is the unpredictability presented by chaos as presented in randori (often defined as "seizing chaos") type training, otherwise regimentation alone with no element of the unexpected can only bring more regimentation. This is the balance I referred to earlier. I don't think there are any systems who are solely regimented in their approach. If there are then they will be subject to the pitfalls you indicated and will never approach spontaneous expression.
The thing is though, even in styles that are known to utilize a non-regimented or systematic approach, the practice of cooperative kata alone does not train one to accomplish takemusu Aiki either, since the rote repetition of form, even in the form of cooperative waza does not train spontaneous ability. So in this light the juxtaposition and ultimate question is not about systematic methods vs the non-systematic ones, but about methods that include and utilizes chaotic elements as a teaching tool in contrast to methods that do not use chaos as a tool to train spontaneous expression.