This is valid, that being said there should've been the ability to prestige your culture at least because it feels so weird that some cultures just artificially collapse when the game says so while others can more naturally transcend into a fitting successor.
I think the fairest way of designing this is to primarily, if not exclusively, choose civs which (a) are defined in a sort of dynastic or imperial manner and (b) absolutely did not survive a particular era. We see this quite comfortably with the India and China civs, but also with a lot of other civ choices. Egypt, Rome, Greece absolutely do not survive past the antiquity era and in no way resemble their modern counterparts. Same thing with the Normans, Songhai, and Spanish Empire.
There will still be some fudging and disappointment, depending on what pathways are chosen, but I think some pathways will be totally culturally acceptable at launch. In rough order from least to most offensive:
* Maurya -> Chola -> Mughals and Han -> Ming -> Qing. Not offensive at all. Except maybe if we consider Tamil/Muslim secessionist movements in India, or any residual resentment toward the Manchurians, but overall these track very much with modern identity consensus. Now, if we try to connect Maurya to Qing with Tibet at some point, possibly offensive depending on whether we view any inclusion, even one being taken over by the Qing, better than none; I personally think it might be in the case of Tibet, a little act of defiance that will persist with little Tibetan temples breaking up the Chinese landscape. But I digress.
* None of the European/Middle Eastern pathways are going to be super offensive. Greece ->Byzantium/Abassids makes sense. Rome -> Normans/Byzantium makes sense. Norse -> Normans would make sense. Normans -> France/England/Italy makes sense. Byzantium -> Prussia/Russia makes sense. Egypt/Sasanid/Sumeria -> Abassid -> Ottomans makes sense. Sasanid -> Timurids -> Mughals will make sense. Etc.
* I don't think Polynesians will at all be disappointed by a pathway of Tonga -> Maori -> Hawaii led by a Samoan leader, as Polynesians are generally quite proud of their shared heritage which all sprouted forth from the Samoan empire, and each people hit a peak in different eras.
* Similarly, I do not think the Shawnee will be offended if they naturally progress into the Anishinaabe, because they have very positive relations with the Anishinaabe, who also happen to be perhaps the best modern representation of Tecumseh's vision of intertribal unity. And the Mississippians don't exist anymore so are very up for grabs.
* I don't think the people of Niger will be offended by Numidia -> Songhai -> Hausa, as their cultural history is well-defined by both the Songhai and the Hausa. Whereas by contrast it would have been weirder for modern day Malians to progress from Mali into a civ primarily in Niger. And I don't think Amazigh/Moroccans will be offended by Numidia -> Songhai -> Morocco because that pathway will likely be united by a cultural Moroccan/Berber figure like Diyha or Sayyida Al Hurra and contain both ancient Numidian/Berber and modern Moroccan/Algerian heritage much like the region holds today.
* The Aksum -> ??? -> Buganda path is going to be weird, but to sum up a lot of vetting of options is probably connected by Kilwa as representation of the Swahili coast. There is a good chance Ethiopia will be in the game at launch (or ultimately in DLC) just to give Kilwa a second option to progress toward, so I don't think modern Ethiopians will be offended (plus, Aksum rides a weird line where it can be "claimed" by both modern Ethiopians and modern Eritreans, which in a way avoids conflict for now). Similarly, modern Swahili people can't be too offended because Kilwa covered a range of modern regions and is settling on perhaps the best
modern representation of Swahili semi-autonomy, Buganda. And Buganda can't be offended by this roundabout path through the antiquity and exploration eras because its probably predecessor, Kitara, is so poorly attested that we really
can't make a Kitara civ for it to proceed from.
* Khmer to Siam by way of Majapahit is stretching a tad, but under Rama V all three can be connected by the Mandala state philosophy and some overlap with Funan and Srivijaya heritage. Modern Indonesia is very different from Majapahit Indonesia after both the advent of Islam and the Dutch, so I don't think Indonesians will be very offended that the Majapahit don't persist. And further DLC will likely bring in Burma, maybe Malaysia, and most importantly a likely Funan leader in Soma, that will help coalesce the shared cultural heritage better. I could see Indonesia wanting some better treatment at some point with maybe Srivijaya and Brunei in DLC (which would be awesome), but so far that's only one potentially mildly slighted "modern" culture.
* The problem with Korea and Japan, fundamentally, is that they both practically demand 3-era structures for being so isolationist (same issue Vietnam will have, although with more flexibility between the Champa and Philippines), but were in no way involved enough in other civs' business to really help flesh out and participate in alternate pathways. To have two or three Korea or Japan civs in the game at launch, with the number of 39-45 civs that we are looking at, would be parasitic. The Han -> Silla -> Meiji path will absolutely be fleshed out by DLC to include, at minimum, Joseon, probably Goguryeo leader, an Edo/Ainu civ, and probably a shared antiquity civ like the Yayoi which is the best, albeit imperfect, option. They will be fine and made whole quite soon enough, although I do think both Korea and Japan will not be fully satisfied at launch and maybe borderline offended. I fully, fully expect that, by the time the game launches, Firaxis will be advertising a Korea/Japan DLC pack on the horizon, possibly as soon as after the Right to Rule pack. It's even possible the Right to Rule pack
is the Korea/Japan pack if it isn't an expected Goth/Gaul/Franks pack.
* And finally, we get to the worst. In some ways, Latin America is equally isolated from the rest of the world as Japan/Korea, but what it really
wants is at least two pathways, one Mesoamerican and one South American. We have not seen any evidence for, and some evidence damning, the possibility of the Aztecs, or an antiquity era South American civ (which would most likely be the Muisca since we know the Inca need an Andean civ to progress from and other options are poorly documented), in the base game at launch. That may change. But I think, at launch, the entirety of Latin America is threatening to get a single three-civ line, just like every other region (West Africa, East Africa, Southeast Asia, Polynesia, and Korea-Japan). Absent seeing evidence of Aztecs shortly after the time exploration era is announced, we are
not getting a Maya -> Aztec -> Mexico line; there is no reason to skip the Aztecs by jumping back and forth to the Inca. Meaning that at launch we would instead be getting
Maya -> Inca -> Gran Columbia, which I think with a return of
Simon Bolivar almost works as being united by the
Isthmo-Columbian region and a
history of resistance against Spanish colonial power. Brazil may come along too as a second option for the Inca to progress toward. Now, I
hope this isn't the case. If we see evidence of Aztecs, we may instead get the proper three-act Mexico in addition to something like Maya -> Inca -> Brazil (which itself would be offensive but at least prevent Inca from jumping places even less sensible like America or Hawaii). Point being, South America is
highly likely to offend people at launch in some way, and I think maybe Maya -> Inca -> Gran Colombia under Bolivar may be the
least insulting pathway. Because even with Maya -> Aztec -> Mexico, unless the leader associated with it is Spear-Thrower owl as an attempt to unify bridge Mayan and Aztec heritage (and I think the time has passed for his reveal), it is offensive for the Maya to completely disappear under the Aztecs. Not even Benito Juarez, who in many respects is a very sensitive leader choice, can fix disappearing modern Mayan heritage that hard. So I think the fairest solution is Simon Bolivar leads the most resistant Spanish colonial powers (Maya and Inca), and we can then flesh things out with Aztecs, Mexico, Muisca, and hopefully some Guarani/Mapuche representation, in later DLC. But, honestly, by rights, this region should have been releasing with two full pathways: Maya -> Aztecs -> Mexico (Spear-thrower Owl); Muisca -> Inca -> Gran Colombia (Simon Bolivar); aside from a little jilting by the Mayans and Peruvians at not making it to modern era, at least they would have leaders representing their overall cultural/political heritage.
Grand summary of people would likely/might be offended at launch:
* Mayans/Yucatans (there will never be a modern Maya in civ, but being forced to be subsumed by Aztecs/Mexico would still be sore spot for modern Mayan heritage. And otherwise jumping to the Inca is equally as insensitive. Although maybe there will be a bit of pride in being treated as the "epicenter" of Latin America to counterbalance that?);
* Peruvians (there will never be a modern Peru in civ, so we can only do so much with Simon Bolivar, or really any civ);
* Colombians (in the event there is no Muisca, it will be weird for them to be represented by the Maya in antiquity) (I don't think Venezuelans, Ecuadorians, or Panamanians will care quite as much);
* Brazilians (I more and more think they might just skip Brazil at launch until they can properly develop the Portuguese legacy, the only reason I think it might be included is to give Inca a second progression option that isn't...Hawaii or America).
* Koreans (inevitable but likely placated with clear promise of DLC)
* Japan (inevitable but likely placated with clear promise of DLC)
* Mayyyybe Indonesians (likely to be remedied with at least Borneo, and maybe Srivaja in the future)
Conclusion: Not many people actually will be offended by these particular civ progressions. Korea/Japan will be dealt with swiftly. And Maya -> Inca -> Gran Colombia offends all three cultures equally. And I have suspicions that if we are going to see any "changes" in the roster leaks we've seen prior to launch, this is by far the biggest target for improvement. The devs would push Aztecs and Mexico forward, and release with Maya -> Aztecs -> Mexico in addition to Maya -> Inca -> Gran Colombia, with possibly Muisca squeezing in as well fully split off the SA line. They might not change any plans to have Benito be the leader instead of Spear-Thrower Owl, but he's the second-best option as a native Zapotec president, so it comes pretty close to the best they can do (and they can/should still give us Spear-Thrower Owl later).