IMHO, the units should have more statistics (as in Age of Empires etc.), e.g. strengths and weaknesses against other types of units, a better bonus of stand-off units like archers and another concept of range in these units. Maybe there should be a special "battle mode" in the game, where you could place the units just like in Real Time Strategy games and watch the battle being influenced by the position, strengths and weaknesses of the units.

I think you are talking about Total war. It isn't the same game. Civ is about rising a civilization. would be very long to play

its called a water weasel it was used around 1944 and i think it would be a good idea for a new unit beacuse you could drive into the sea from the land :)