My co-op friend just dropped the coolest mode suggestion I've ever heard: The option to see your starting location and then choosing your Civ. This would be a cool optional rule for certain games, where, instead of generating the map on the basis of the Civ, choosing the Civ on the basis of the generated map. This could lead to some very interesting player choices, where you'd might have three or four civs optimal for a specific start (let's say navigable river and tundra, or an island start with lots of rough terrain). The player gets the option to adapt to the start, instead of choosing a certain strategy based on the playstyle of the civ chosen beforehand.
What do others think? I think this would be a wonderful game mode for later in the production stages, that enhances replayability and introduces a new way of interacting with the map and the strategic aspect of the game!