My 2 cents regarding making an interesting battle field:
The asymmetrical path of the river creates a more organic battle, there are advantages/disadvantages to each Zone.
Different areas require different battle skills, like the close quarters of town vs more open country
Elevation changes, both mountains and mole hills, play a big part in strategy
Even a small hill can alter the angle of the TBU making a tank defensive
Firing 'lanes' that allow sniping across certain points of the field, but not all, creates the need for constant awareness