I read this TL a few years ago and found it amazing. So I was pretty excited to see this back on the main page!I
If you've never read Peter Green's Alexander to Actium you really should, it's a 360 degree view of the whole Hellenistic age covering everything from philosophy to literature to the details of how the Successor kingdoms worked on a bureaucratic level. One cultural theme that really seems to leap out from this era is a sense of the loss of tradition and poleis, and the loss of civic and even personal agency by individuals, demolished by the new autocratic kingdoms and the will to power, whose rulers themselves are playthings of Tyche or fate. This came with a corresponding move from focusing on civic, public virtue to personal, private virtue, and a tendency to minimize the traditional cults of the Olympian gods in favor of more coherent, personally applicable philosophies like Stocism and Epicureanism, and later, mystery cults like the Eleusians. In the East, I don't actually see this cultural trajectory changing much: if anything, we have a more gargantuan empire, ruling these Hellenes for longer, so these tendencies may be accelerated. Epicureanism in particular, or something much like it, may receive a boost from the influence of Buddhist philosophy. The Epicurean ideal of ataraxia, or imperturbability, has more than a passing resemblance to the Buddhist ideal of non-attachment. I suspect that the Orphic Buddhism that back-proselytizes to Asia may resemble Epicureanism in many respects. With the greater consciousness of external forces to determine one's fate, there was also a tendency to develop totalizing systems like the Stoic insistence that the motion of planets precisely influenced events on earth; I could see the Babylonian transplants in Thebes being influential in popularizing astrology. This also manifested as seemingly opposing trends of nascent monotheism, with Zeus, Tyche or other gods being emphasized as having distant but paramount control over the universe, and as a tendency to deify rulers, who, unlike the Olympians, undeniably had immediate power on Earth. The Persians are likely to identify Zeus with Ahura-Mazda, and I do wonder if Zoroastrian influence may yet find a home somewhere in this alternate Asia. I can easily see the later Helleno-Persian dynasts cultivating a cult around the ruler much as the Ptolemies and Seleukids did.
The Western Hellenes, OTOH, may postpone these cultural developments, at least temporarily. I think with more preserved agency for individual and poleis the cultural tendencies will run more towards action in the world as opposed to cultivating detachment from it. The hints of recurrent Pythagorean rebellions seem like they are running in that direction.... the cult of Herakles was also widespread in Magna Graecia and I could see this influencing culture there as well... Carthage cultivated syncretism between Herakles and Melqart to take advantage of this OTL. I'd need to think more about what this would look like. Ironically I could see a Zoroastrian-influenced system appealing to them, with its emphasis on this-world action, were it not for its Persian taint.
Speaking of Carthage, the idea of a Greater Punosphere is fascinating.... I could see the Punic alphabet being used as far north as Britain TTL. I also doubt Gadir would sit idly by and let the Tartessians monopolize the Atlantic seaboard... Might we see greater interaction with Cornwall, and maybe, eventually, into the North Sea? Or perhaps we will see more settlement in West Africa, on Cape Verde and the other islands just off Africa. I do think, with W Africa being more integrated into the world system, that the New World will be discovered sooner rather than later so long as this brisk trade continues.
How far did the Tinian Empire actually extend at its height? From the text, it sounds like they took over Italy and Massalia but it's not clear if they got any farther than that. The religion of Gallia TTL must be something else, being a melting pot of Etruscan, Hellenic, and Celtic influences. The Tinian precedent of a "Mandate of Uni" is soemthing I think will persist in the Averni successor states: it's a convenient way to justify one's rule over such a diverse and disparate population. I wonder if some ruler or priest will eventually formalize the druidic religion as Zoroaster did to Iranian paganism. On another note, I remember you mentioned Sardinia had become Etruscan... what happened to the Carthaginian presence on the island? Caralis was founded as a Punic city and they were there first....
Also, I can't help but notice very little has been mentioned of Egypt so far. ITTL Egypt, apparently, gets to restore a native Pharonic dynasty instead of having that tradition come to an end under the Persian, Ptolemaic, then Roman boot. I feel that that in and of itself deserves a post. Apparently they become Buddhist eventually, which is interesting. I wonder how well this plays with the native priestly caste, who even the Ptolemies could not avoid dealing with....
I also wonder what the impression of the Agnimitrids was, back in India. OTL much of the Persian treasury was shipped west to Pella after Alexander conquered the empire. Here, that gold is likely going east instead... With such an inspiring example, I wonder if TTL's Chandragupta Maurya might not get started sooner on establishing hegemony over the subcontinent, and dream of lands beyond...