As I understand it, the unit frontages are realistic in terms of distance occupied (not sure about unit depth).
If it was scaled 1:1, I imagine the frontages wouldn't change but the soldier symbols would become much smaller.
And how does that relate to the terrain? The terrain and terrain features I think are heavily abstracted. For the purposes of computing combat, all villages have four access points rather than being modelled as accurate representations, so the space inside them is meaningless. Also, forests, for example, occupy a realistic area with regard to the frontage sizes of units, but are represented by far fewer and bigger trees than would be the case in a 1:1 scale.