Combat zones should have the land from the zone the combat occurs in, along with the attributes of that land.
A forest gives ranged protection.
A hill gives melee protection.
City walls grant defence bonus.
Outposts grant ranged units a farther attack.
A road allows additonal movement along that stretch.
Perhaps there is a small lake, and you have units that can swim.
Perhaps you can cast a 'wall', between two mountains, forcing your opponents into a bottleneck.
Stuff like that...
