So far I have done two blogs about settings for future Assassin's Creed games; one for Feudal Japan and one for 19th Century London. Now we all know the most wanted settings for future Assassin's Creed games, but we don't really know what people want from them. What people want from the gameplay, story, characters, locations, etc. So I'll be making several blogs where based one location and time period so people can talk about what they want.
So, anyway, Ancient Greece. As Superman mentioned, it would be a good idea to explore more about the First Civilisation and the Pieces of Eden. A lot can be done; Mount Olympus, cities like Athens, etc.