One thing that might be kinda cool for Civ would be if there were wonders that you could use to pick up additional civilizations traits. An example of such wonders might be:
Temple of Solomon: (Ceremonial Burial) Grants builder or conqueror Religious civ trait. Made obsolete by Theology.
Plato's Academy: (Alphabet) Grants builder or conquerer Scientific civ trait. Made obsolete by engineering.
This would work for all the traits except sea-faring and expansionistic. The addition of the extra trait is balanced out by the build investment in a wonder that will only last for 1 age and then is lost. They can be additionally tweaked by adding minor bonuses (become a tourist attraction, Academy counts as additional library, Temple of Solomon makes an additional person happy, etc.) or varying the amount of culture given to a wonder.
Temple of Solomon: (Ceremonial Burial) Grants builder or conqueror Religious civ trait. Made obsolete by Theology.
Plato's Academy: (Alphabet) Grants builder or conquerer Scientific civ trait. Made obsolete by engineering.
This would work for all the traits except sea-faring and expansionistic. The addition of the extra trait is balanced out by the build investment in a wonder that will only last for 1 age and then is lost. They can be additionally tweaked by adding minor bonuses (become a tourist attraction, Academy counts as additional library, Temple of Solomon makes an additional person happy, etc.) or varying the amount of culture given to a wonder.