Well unit movement is pretty well known at the time. FE, a warrior can move two tiles and not more across a road. there is still the terrain penalty that has not been mentioned but my opinion is that it has been left unchanged. The arc refers to the shooting trajectories of any given ranged attacks.
As for Earth curvature and zoom levels, there isn't any mention of such things but ity doesn't mean there will not be present in the game. I don't see any reason to not have these functionalities implemented.
I guess you are expecting too much from a single preview, but cross-refs are a safe way to get a good understanding of what is coming on.