I like the idea of different barbarian clans attacking each other, but i don´t like the idea of barbarians having their own tech tree, 4-5 cities, settlers and everything that follows. Then they can´t be counted as barbarians, but more like a Civilization for itself. I wouldn´t want to see that. Barbarians having transport ships, to deploy their troops sounds interesting, but should only be included on higher difficulties. The archipelago map, would be like a living hell if barbs starts to conquer their own islands and starts sending troops to vanquish other civilizations. But it would make the navy more important on maps, where having a powerful navy counts for nothing. About the animals, i like the concept. Because it makes early expansion a bit more difficult, and they usually match with the surroundings. Although i hate seeing a lion walking around the tundra.