Quote Originally Posted by Alhanelem View Post
No, I'm not. Any development team has a certain limited amount of resources. As you make an area larger it requires exponentially more resources to create and populate with assets and content (Unless you generate it proceedurally (e.g. randomly), but that wouldn't work for a game like this).

So, you'd rather that "75%" of the area drop you to your death or be able to fall into and not get out? That's why there are walls, both visible and invisible. It is much more difficult to create an area with such great detail and have it be 100% walkable. You're basically limited to rolling hills and bland landscapes (See: WoW) and concentrating details in specific locations.
I don't think you've actually looked at a lot of the maps. Take that image of the North Shroud, for example. It is in no way surrounded by bottomless cliffs and yet the zone is made up of a bunch of absurd canyons funneling you from one quest node to the next. It's awful. There are tons of rocks and rivers and pockets of inaccessibility that have no business being walled off, plain and simple.