I don't think wonders should have continent based effects, especially considering how few people are actually aware of when continents change boundaries and where those resulting continent boundaries are. Wonders such as Notre Dame, should instead just apply for something like maybe....
- cities within 15 tiles of the capital or
- the oldest 8 cities of your empire by date you most recently acquired that city
This definitely makes which cities experience continental effects a lot less arbitrary.
Regarding successor states and independence of colonies, IMHO I think the less civ spawns and city/unit flips, the better. I think you should be allowed to play through a civ and as their successor civ if you manage to survive.
Example civs:
Persian Empire--- representing the Achaemenids, Parthians and Sassnids
Capital: Parsa => Ctesiphon (same tile as Baghdad, moderate likelihood)
Leaders: Cyrus, Xerxes,
Anushiravan
Unique Unit(s): Immortal,
Persian Cataphract (slightly cheaper and weaker than knights available with earlier technology and without levy)
Unique Power(s): Power of Satrapy, and either Power of Parthian Tactics: Chariots and Horse Archers get free Flanking I promotion, or Power of Silk Route Trade: get +2 gold per turn for every luxury resource imported or exported
Unique History Victories:
- Persians in general need better UHVs. What these could be would depend on how Leoreth reworks the combat system. In general, there would be 2 generic moderately difficult Persian UHVs, and 1 difficult UHV representing the Achaemenid empire, and 1 difficult UHV representing the Sassanid empire. Only need to complete 3 to win.
- an idea for the difficult Sassanid UHV: Control 8 civilization spawn spots in 610AD (historically was Persia itself, Babylon, Phoenicia, Egypt, Arabia and Turkey; historically unattained but might be possible in game could include Byzantine, India, Greece, Rome and Ethiopia).
Empire of Portugal and Brazil --- representing Kingdom of Portugal, United Kingdom of Portugal Brazil and Algarves, Empire of Brazil, FR Brazil
Capital: Lisbon => Rio de Janeiro (low likelihood in 1750; but high likelihood in 1815) => Brasilia (medium likelihood in 1950)
Leaders: Afonso Henriques, Joao II,
Pedro II
Unique Unit(s): Carrack seems sufficient
Unique Power: Power of Exploration seems good to keep, either Power of Deforestation: clearing jungles produce +50 hammers after Electricity, or Power of Agricultural Industry: Whereas other civs get a +2 gold bonus for Sugar and Spices and +1 hammer for corn between the years 1450-1700, Portugal/Brazil gets that bonus from 1450 until end of the game.
UHVs:
-Again, 2 moderately difficult generic Portuguese/Brazil UHVs, 1 very difficult Portuguese UHV (maybe have at least 1 more city than any other Western European state in South America, at least more cities than any other Western European state in each of the following groups of regions 1) South America, 2) Africa, 3) Asia) and 1 very difficult Brazilian UHV. Only need to complete 3 to win.
Regarding Rigo's ideas. A lot of them are interesting. I definitely can see Aztecs(Mexicala peoples) and Mexico could be one civ linked by dynamics names. If Aztecs get conquered, I think it makes sense for them to respawn if owner civ stability is low as Mexico. Otherwise, if the Aztecs survive, I think they should just make a peaceful dynamic name and leaderhead transition into Mexico.
Although having a Central America civ works well with the way the Maya are currently set up, I think a civ like Gran Colombia would have much better playability value since they would represent a larger geographical area that might even encompass a good portion of Central America. (as in the case with Panama for a while belonging to Colombia).