ORIGINAL: ColinWright
I see this sort of thing as just implicit in 'open' terrain. 90% of the dry land on the earth is at least this endowed with defensive features. Even a supposedly 'flat and open' state like Nebraska would have terrain of this type over 90% of it.
Yes, that flat state of Nebraska. Within the borders of Nebraska lies the Sand Hills. 20,000 square kilometers of sand dunes, some hundreds of feet high. And don't forget the Pine Ridge in the Northwest. Looks like the Black Hills what with the rock faces and Ponderosa Pine. Very little of the state is as flat as the Platte River valley I can always tell if someone has never been here or simply zoomed through on I-80. It's the ones who talk about how boring and flat it is. [:D]
But yes, I know what you mean about how there is very little terrain with absolutely no cover. However, I think that's more of a tactical matter isn't it? For operational purposes a 'flat' state like Nebraska or Iowa could be considered to be either 'open' or hilly and for the most part with no woods. There are lots and lots of creeks in both states with deep, steep sides. Wonder how that would be modeled. Certainly not crossable without engineering or bridges.