Hi Mark-- no Punch and Judy intended! I just thought that if I claimed that Uranus works as a ruler of Aquarius, I should back it up with some chart interpretation. Perhaps another thread sometime could focus on taking a problem like, "Why were these men great scientists?" and then having different participants apply their own methodologies to the natal data, because I think we would see areas of overlap as well as difference. I find Uranus to be extremely helpful, but I acknowledge good astrology where I find it.
I'll come back to Aquarius momentarily.
I agree with most of your long post to me.

Notably:
I think the Ptolemaic tradition with its naturalistic, aristotelian approach tended to sideline the Sun as a natural significator of the higher mind or creative spark.
It was of course Ptolemy's view that went on the dominate Perso-Arabic, Latin and renaissance astrology.
In Ptolemaic astrology the Sun becomes like the Director behind the camera but seldom in view
My particular interest in traditional astrology is in ferreting out some of its origins, notably the transitions from ancient cultural astronomy to astrology proper.
It is in these earlier cultural contexts that you will see extra-astrological ancient sources describing a link between the sun and the intellect. Apollo for the Greeks was the clearest example, after he historically became assimilated to the earlier Greek sun god Helios. Apollo was the god of prophecy, the medical arts (pre-Aesclepius) and a bunch of traits that today seem very 9th house (where the sun joys, perhaps not coincidentally.) He had these connotations chronologically
prior to the Greeks giving him the sun-god role. (Cf. our current distinctions of Apollonian vs. Dionysian.)
Previously we find the Mesopotamian sun god Shamash having some associations with intellect, but perhaps more powerfully with associations of the sun as king, judge, and authority. (Rochberg,
The Heavenly Writing.)
I took the Avelar and Rebeiro description of the sun as metaphorical, or based upon current understandings of the astronomical sun. It seems almost like it came out of a science textbook.
The Egyptian sun gods (on whom the astrological house system was probably based) don't seem intellectual at all. They do appear as kings (pharoahs) and judges; which seems to be the main use of the sun in Hellenistic cookbook delineations. Thoth, the original Egyptian god of the mind, was originally a moon god. He got assimilated to Hermes under the Greek influence.
(The gospel according to John is another posssible mind-sun link.)
The following assessment has been really hasty, so feel free to catch me up on any of it:
What surprised me was how little I found about the
qualities or character traits of the sun in the applied astrology handbooks, in doing a quick check of Aratus (treatise on cultural astronomy, 3rd century BCE, )Dorotheus, Manilius, Valens, Ptolemy, Firmicus Maternus, Rhetorius, and Al Biruni.
Valens was actually the only one who discussed the qualities of the sun-- and he was the one author who made the intellect connection. So little is known about him that we can't say whether he described a much more widespread astrological interpretation of the sun, or whether his was a one-off, possibly based on his equating the sun to Apollo.
Possibly the hermetic literature would give a different interpretation-- I didn't check it.
More could probably be gleaned from an in-depth scan of the cookbook sections of how the Hellenistic astrologers used the sun in chart interpretation, but so far as I can make out, they didn't say much if anything on the sun involved in intellectual matters.
Of course, the sun was and is just crucial for the diurnal and annual nature of the horoscope, plus other sorts of chart delineations, as you point out. It just didn't seem to relate much to the intellect.
I find it really helpful, in approaching a primary source, to consider what was the author's project in writing it. Ptolemy clearly wanted to strip away all of the magic, religion, mythology, and personalities out of his textbook
Tetrabiblos. We can see Valens as the great compiler and practitioner, but Ptolemy essentially wrote a "science" textbook. Valens (notably in the Riley un-indexed translation) is difficult to read for quick referencing purposes; whereas for all its faults,
Tetrabiblos is clear, systematic and very easy to follow. This probably accounted for a lot of Ptolemy's subsequent popularity.
So to come back full circle to the sun's domicile in Leo and detriment in Aquarius, I am not sure how much those ancient astrologers really used planetary detriments in chart interpretation.
Valens p. 40: "Let the sun, moon, Jupiter, Mercury be in Leo, Saturn, Ascendant in Libra, Mars in Gemini, Venus in Cancer. This person was fortunate, a leader, dictatorial, possed of royal fortune, and in sold possession of great property...."
"...sun, Mercury, Venus, Ascendant in leo, Saturn in Taurus, Jupiter in Sagittarius,
Mars in Libra, moon in Capricorn. This person was a governor, a master of life and death
because the stars were found in their own domains."
So in Valens's first example, we have a hyper-Leo, but his attributes were wealth and leadership, not intellect. In the second example, we have another Mister Big, but he's no philosopher-king. Significantly, having his Mars fall in Libra and his moon in detriment were apparently no hindrance to his success in life. Valens could still say that his stars were found "in their own domains," notwithstanding.
Intriguingly, the Roman emperor Augustus Caesar (63 BCE-14 CE, Barton,
Ancient Astrology, 40) was so taken with his horoscope that he had coins struck with pictures of his moon in Capricorn. Apparently the astrologer didn't bother to tell Augustus that his moon was in detriment. Possibly because detriment wasn't in widespread use then.
I've probably missed something, but I couldn't find mention of detriment or falls in Dorotheus (1st cent. AD, but heavily glossed by a Muslim editor.)Manilius (1st cent. AD) talks about signs in antagonism to one another, but since he doesn't mention domiciles specifically and his sign-ruling gods were tutelary rather than planetary, we also don't get an Aquarian detriment for the sun. Surprisingly I couldn't find detriment in Ptolemy. did I miss something?
The exaltations are apparently much older than domiciles, showing up in Mesopotamian and Egyptian sources long before the development of Hellenistic astrology. Initially exaltations seemed to refer to specific degrees or small parts of a constellation where a planet should be extra-strong. Firmicus Maternus (280-360 CE, 2:3) doesn't seem to go by entire signs for exltations or falls, just specific degrees, one per sign. He gives domiciles but not detriments as the sign opposite the domicile, so far as I can tell.
So... the affiliation of the sun with intellect in Hellenistic astrological
practice would seem marginal; and the idea that if planets have exaltations, they must similarily have falls ("depressions.") shows up as a worked-out system in Mr. Pt.
Ptolemy, intriguingly, associates Mercury, not the sun, with intellect in his section on astro-geography (II:3.) "The inhabitants of Hellas, Achaia, and Crete however, have a familiarity with Virgo and Mercury, and are therefore better at reasoning and fond of leanring, and they exercise the soul in preference to the body." He's got a few regions ruled by Leo and the sun, but these have no reference to higher learning.
Of course, Time Marches On, and significant developments in astrology occuring after the Hellenistic period might have stressed the points that I don't see (yet?) in earlier work, but I'll have to let someone else discuss them!
(p. s. Mark-- do you know who first introduced the 4 elements to astrology? Valens book I?)