Now that I am convinced that it will be shogun 2, I think that CA has to work particulary for this new opus:

-on battlemaps (number and quality)
-accurate uniforms and weapons
-a lot of different units
-on bows: more visuable arrows and arrows remain in dead bodies!
-all the animation with piques or lances, lances or piques crossing the bodies
-buildable defenses in campaign but also in custom battles
-cities with all the houses available to units.