I will just copy my Consolation Post here, I hope it doesn't violate any rules? I was at first very scared of civ switching, but then calmed down a lot after thinking about it, and wanted for many people with similar reaction to see my reasoning and hopefully be consoled.
CONSOLATION POST FOR PEOPLE SCARED LIKE ME AT FIRST
Keep in mind that in Humankind the system was forced upon the player largely due to this game's horrible mod support and civ switching being enforced by its mechanics. It is highly possible that
"classic mode" is either going to be a popular
mod (or maybe even
official option added by Firaxis if they decide negative response is too high).
Also, Humankind's system was made terrible by the fact you made
six transitions and the game had essentially
no leaders (avatar system was godawful). Meanwhile in civ7 you're going to have
only two transitions plus you have leaders (plus, again, I highly expect mods and modes for AI civs remaining old civs, or going for the closest historical paths etc). So you have
much more time to get attached - on epic speed I would spend like 200 turns with each of three civs even if I decided to switch each time and had no "viable feeling" transitions. Much less transitions also means that it is actually possible to fill out sensible development lines using mods, which brings us too...
Finally, this system has
incredible potential once you add mod civs. It allows for epic things such as:
China having progression of dynasties (Han -> Ming -> Qing)=
India having countless possible evolution lines
History of Iran (Achaemenids -> Safavids -> modern Iran);
History of Arabs (say Nabateans -> Abbasids -> any modern country)
History of France (Gauls -> French Kingdom -> French Republic (because why not?? mods will allow that))
History of England (Britons -> Anglo-Saxons -> Great Britain)
History of Italy (Rome -> let's say Florence -> Italy)
History of Germany (your fav Germanic tribe -> your fav HRE state -> Germany)
History of Turks (Gokturks -> Ottomans -> Turkey)
History of Andean civs (Nazca -> Inca -> Peru (honestly I'm fine with it - but you can retain Inca))
more historical America (Britons/Anglo-Saxons -> Great Britain -> America
)
History of any Bantu country (Bantu -> precolonial empire -> modern country)
History of Korea (Goryeo -> Joseon -> your fav modern Korea)
In Humankind filling out sensible transitions was impossible due to their number (and miserable mod scene). But here it is tangible and actually opens amazing opportunities. I can repeat the above with sensible transitions for Indonesia, Philippines, Thailand, Burma, history of Bengal and Bangladesh, Sri Lanka, Armenia, Russia (Slavs -> Muscovy -> Russia), Nordic peoples (Proto-Germanic -> Norse -> Norway), Greece (ancient polis -> Byzantium -> Greece), Spain (Iberians -> Visigoths -> Spain), Ukraine (Rus -> Cossacks -> Ukraine)...
Doesn't this sound glorious? There is a potential in this system to make each historical civilization shine greater than before, with fans creativity.
There will be mods modifying the system or even removing it, there may be official game modes, there will be your agency, which taken together will most probably enable you to see the world of old civ games - but there will be also options for something greater. Humankind never had this potential because six transitions, its systems, its avatars and its terrible modding made anti-immersion inescapable; here we have hope.