This sutta is squarely within the system of the EBTs. Every section of the sutta has parallels in other discourses, so the general claim that this is a one-off, weird sutta is simply wrong.
Some of his contention with the other scholars is correct, in that Early Buddhism is more concerned with phenomenological than noumenal philosophy and so, while a bit overblown, he is correct to nitpick e.g. the use of the word “existence” here, which they are (erroneously) reading in to the Pāli.
I’m also sympathetic to his digression about the colors. The past is a strange place and we know that the ancient ideas about e.g. colors were different than ours. But he doesn’t provide an alternative reading, and I’m extremely sceptical of his contention that “conceptualisation is transparent to the person and would not have been obvious to early Buddhists.” The very same early Buddhists that were routinely attaining high jhanas? They would be less aware of the workings of their subconscious mind than us “enlightened” moderns?! Yeah. Right.
Somewhat related, an interesting talk by David Graeber and David Wengrow called "The Myth of the Stupid Savage: Rousseau’s Ghost and the Future of Political Anthropology. "
They basically challenge the idea that ancient peoples were politically naive, and the idea of a linear progression from simple to complex political systems over time (hunter gatherer -> agricultural societies -> modern states).
I think the same principle applies to psychology / philosophy of the mind regarding the EBTs.
E.g. in my PhD research I am above averagely interested in what is called causal inference, and my opinion is that the EBTs treatment of causality is higher in quality than much of the published research I read.
The four noble truths is a much stronger theory in scientific terms than say the big five personality traits.
Edit: My point being that I don’t see any evidence of the EBTs lacking sophistication.
The basic structure is the same, though a couple definitions of the skandhas differ. Form is defined as being obstructive and divisible, and the definition of perception doesn’t involve colors but rather numbers and extent (few, many, measureless, nothingness). When I read it, I see some Abhidharma influences taking place, especially with the standard Sarvâstivāda definition of form as “obstructive” (i.e., occupying space) and divisible. Overall, I’d say it lends a bit of support to his argument about colors leading modern people to different interpretations. Recognizing things as few or many is more abstract than the direct perception of colors.
True, the specific definitions are slightly different for perception.
In the whole sweep of SN vs. SA comparison, this is I think one of the more closely parallel sutta / sutra. In terms of definitions for example, this SN22.79/SA46 is quite a bit closer than say SN12.2/SA298 on the definitions of different terms of dependent origination.
For the five aggregates, I think the most authoritative analysis is probably SN 22.57/SA42, though as with most “analysis” suttas, it does give a feeling of abhidhamma.
I think it’s an alternative point of view that’s been preserved, and it’s probably pretty old, originally. As @pamirs points out, SA 46 is very close to the Pali, with just a few key definition words that are different. So, I’d read it with the other sutras that define the five skandhas and see how it looks letting them overlap. It seems like early Buddhists tried to not get stuck with just one definition of things to avoid too much dogmatism. At least, that’s how it feels to me when I read at these types of alternative definitions.