I think thescenarios are great but I'm not sure if the civs for those (two native American civs?) should be permanent. Here are my ideas:
Expansion: Age of exploration
Adds Portugeuse, Dutch and Vikings. One scenario would have England, France, Spain, Portugal, the Dutch and the Vikings in a race to find and settle a city in the New World, lasting from 1000-1500 AD. Another scenario (excluding Vikings) would start in 1400 AD and would have the winner be the civ with the largest area in the new world.
Another idea: A Mediterranean pack that adds Carthage and Phonecia.