Is the Eightfold Path sequential?

Recently, a jhāna-enthusiast1 on Facebook was unhappy about the right concentration then right mindfulness article in Dharma.direct #2. It didn't help that he hadn't even read the article prior criticizing.

I offered to him to write in this Debate section, but he didn't pick it up, so I'll cover it myself.

Ultimately, what irked him was the perceived awfulness of reversing the traditional order of “… 7. right mindfulness, 8. right concentration” from the Eightfold path. For him, « the Noble Eightfold Path is quite specifically the path of jhāna. »

Personally, I think “it's the path of jhāna” only as much as the jhāna is what the practitioner needs to free oneself from ‘ignorance’. Wisdom and Liberation from ignorance are the goals of Buddhism.

The specific disease should dictate the appropriate antidote, not the preferred therapeutic course of the doctor… In support of such a perspective, the aggi sutta (SN 46.53) presents tranquillity, concentration and equanimity as mere antidotes to excitement… Then, concentration is merely one of the spokes, a trait to cultivate among several, when it is ‘timely’ to do so: neither a trait to focus particularly on, nor the culmination of the Path.

We could also note that the quest of the Buddha brought him to define the Middle Path, after seeing the inadequacy of asceticism to attain Freedom… but this asceticism was not just based on starving oneself, it was very much in line with practicing the jhāna as the priority (as the Buddha had learnt from his own teachers: Āḷāra Kālāma and Uddaka Rāmaputta).

It's been pretty long established that actually there are two interrelated systems of meditation: one is called the development of serenity… … … …