you're essentially asking "well if you are okay with some level absurdity then why aren't you okay with a completely different type of absurdity
I don't think it's a different kind of absurdity. I think the things that bother you are two more versions of the
same kind of absurdity. I've characterized it as follows: elements that were connected one way in our history being disconnected from one another and allowed in-game to be connected differently.
Must China be defined by the territory it occupied on this-earth's map? No, in fact we can have maps of a different shape from this-earth.
Must China be defined by the kind of terrain it possess in this earth? No, China could have a tundra start.
Must China be defined by the luxury resources it possessed on this-earth? No, in-game China could be famous for furs rather than silks.
Must China be defined by the great wonders it built on this-earth? No, China could build the Pyramids rather than the Wall.
Must China be defined by the religion it has in this-earth? No, China could be Christian rather than Buddhist.
Must China be defined by the governmental system it has on this-earth? No, China can choose Democracy rather than Communism.
Must China be defined by one of the leaders that actually led it on this-earth? You're damn right it must!
In previous games, you've been willing to carve out of a civ almost everything that has made it the civ what it was on this-earth, really substantial elements of what makes China China. Now you're balking at one individual who led it for maybe forty years if he or she had a long reign.
Ok, you'll grant me, that is a pretty irrational hang-up.
But civ switching, you'll say, is way more extreme.
Yes and no. It's not different
in kind. It's a civ-element made available for different combinations in-game than we saw this-earth. When we take the long view of a civ, we will almost always partition its total history into broad phases. Ancient Rome was a Mediterranean-spanning empire, medieval "Italy" was a collection of competing city-states, modern Italy is a peninsular nation state. The age-specific civ-lets are
these differently-assemble-able chunks. So now an in-game civ, Tecumsehland, can have an Egyptian first phase, a Shawnee second phase and an American final phase. (Or alternately, you can define your total civ backwards from your final civ. "Early America--or as that people called itself in antiquity, Egypt--was from its founding rich in agricultural and mineral resources . . .") Admittedly, that those civlets get the names of this-earth civs does represent an obstacle to conceiving of your in-game polity as a single, continuously developing entity. But again, as I said, I think game dynamics will mitigate that.