I disagree. That would be very unrealistic. Right now the battlemaps are supposed to be small areas sampling terrain from the area. If you were to make it seamless, the scale would be absurd. At the distance from the earth that you view of the campaign map, the earths crust would look about as thin as a nickle. If you could zoom all the way in, there could only be two very absurd possibilities: 1. The entire earth in full scale would need to be created (The reasons this wouldn't work are apparent), or 2. They would need to pull and AoE and have the different continents tiny.
If this is what they intend to do, I don't think I will be buying the game. I think the idea would be a total leap from realism that would really pollute the Total War series.

Vuk