The aggregates aren't dukkha; always it is the clinging-aggregates which are so described.
To a certain extent, this is true, especially in light of the First Noble Truth formula.
Yet, there is also the proposition that can claim equal importance, ie yaṁ kiñci vedayitaṁ taṁ dukkhasmin ti
(whatever is felt is included in suffering).
Hmm. Now, despite the presence of the Rahogata Sutta
, from which we might infer that the Buddha changed his pedagogical method in this respect sometime during his ministry (the move would be from "whatever is felt" to the "three types") we can further observe the following materials to get a sense of how feeling was addressed when the Sangha was early:
Sn 4.11 wrote:
"What is the source of thinking things as pleasant or unpleasant? When what is absent are these states not present? What is the meaning of appearing and disappearing? Explain the source of it to me."
This is from possibly, as you once put it, an early schedule of paticcasamuppada. The noteworthy lines are
Now what is the source of desire in the world? What is the cause of judgments that arise; of anger, untruth, doubts and whatever other (similar) states that have been spoken of by the Recluse (i.e., the Buddha)?"
"It is pleasant, it is unpleasant," so people speak in the world; and based upon that arises desire.
Thinking in terms of pleasant and unpleasant is shown as part of the problem. No distinction is made between mental and physical, either. Now, later in the Suttanipata, but also in the Samyutta Nikaya, we can find these lines:
SN 36.2 wrote:
Be it a pleasant feeling, be it a painful feeling, be it neutral, one's own or others', feelings of all kinds — he knows them all as ill, deceitful, evanescent. Seeing how they impinge again, again, and disappear, he wins detachment from the feelings, passion-free.
(I think the relevant lines from the Sutta Nipata
are as follows:)
whatever is felt —
neither pleasure nor pain,
within or without —
seeing its passing away
at each contact,
he knows it right there:
with just the ending of feeling,
there is no stress
coming into play.
Now, translating this poetry is obviously difficult stuff, but the gist is that feeling was taught in the context of an early formulation of paticcasamuppada, which means that the connection between feeling and desire was made explicit. Additionally, arahants were thereby described as released in the face of feelings of all kinds, due to the lack of clinging.
I note the absence of five aggregate talk altogether. This tells me that stressing upadana during talk of the five aggregates, a potentially later pedagogical structure (made more likely, perhaps, given that the commentaries love to define various phrases in the Snp as referring to them), is appropriate and accurate.