Each of the limbs of yoga are both cause and effect, and all of the limbs of yoga are interconnected within us. So one person's structured practice may be another person's symptom. Personally, I'd rather rely mainly on practices than on symptoms. That's why in AYP we favor the practice over the symptoms. And, as you know, we have plenty of practices.

I agree with you that kundalini of the dramatic symptomatic kind is not a prerequisite or ongoing feature of enlightenment. The drama of kundalini is purification (the friction of awakening energy passing through obstructions) and not the end result. However, the subtle characteristics of kundalini that evolve to permeate the neurobiology as ecstasy and the refinement of sensory perception are essential to enlightenment. You may not call that kundalini. But it is, in fact, the eventual refinement of the flashy versions of kundalini that some people experience along their path. It is the emergence of our ecstatic nature, ultimately to be dissolved in stillness. In AYP we call it the rise of ecstatic conductivity. That and abiding inner silence (stillness, the witness) are the two pillars of enlightenment. The equation looks like this:

Stillness + Ecstasy = Unity (enlightenment)

In AYP, we use deep meditation for cultivating abiding inner silence (stillness).

Ecstasy (ecstatic conductivity/kundalini) is cultivated with spinal breathing and other pranayama methods (including kumbhaka), plus asanas, mudras, bandhas, and tantric sexual methods.

Rising stillness and ecstasy are blended together (in the equal sign), with samyama, karma yoga, and self-inquiry. Each of these finds its fruition when performed in stillness (presence of witness), which we call "relational" in AYP. The result is "divine radiance."

Bhakti (divine desire) plays an over-arching role in all of this. Bhakti is the fuel of all spiritual progress. Even the tiniest desire for growth contains all of these elements of unfoldment within it, and stimulates them directly.

Now, some will say that stillness is enlightenment, and others will say that ecstatic kundalini is enlightenment. The truth is that both together form enlightenment. It is the union of stillness (shiva) and ecstasy (shakti) which brings an unending outpouring of divine love and the unity experience in daily living, i.e., Oneness. In AYP we also call it "stillness in action."

This process is inherent in the human nervous system and is universal. Different paths emphasize different aspects of its development. In the end, all the bases will be covered. It is a natural process, once it gets going. Our job in daily yoga practices is to get it going and keep it going, without overdoing it (self-pacing). Then we come to know what it is by direct experience.