stealth_nsk
Deity
Politically all 3 versions of China are monarchies.I think the difficulty is that Modern Age ends somewhere in the early 1960s-ish with the science victory representing the moon landing.
Obviously between the 1960 and current day the United States has changed a great deal culturally, but politically it’s still the same system of government, and it makes the Civ switch seem very subtle (or non existent) compared to other era changes.
If we speak about immersion, that's a matter of personal preference. To me, 19th century USA with it's slavery, civil war, settling on the west, conflicts with Native Americans and so on is very different from post-industrial version of the USA.
And gameplay-wise the difference is even bigger. Frontier Expansion? Gold Rush? Wartime Manufacturing? Prospector? Steel Mill? Most of modern USA properies don't make any sense for 4th age. Same with UK.