I hope people keep in mind that at least right now we have access to one aboveground area which happens to be on the edge of some mountains? Are you expecting to be able to crawl up one side of it and down the other? To me, the current map fits the terrain. If we were in the middle of a plain and somehow constricted to a road, I'd understand the concern.
For being a giant cave, the underdark area we have access to so far seems pretty open to me. Being underground, they could have constricted you to a maze of tunnels.
Not sure what the expectation people have here is: something like Skyrim? That gets tiresome after a while. I personally like what they've done so far.
And hence the hope that we are not eternally on the edge of mountains, along a coast. If we say nothing - chances are that there will be a whole lot more mountains or similar features. Perhaps magma on a fire plane or travelling deep in an ocean crevasse where giant cliffs rise up from it, but the same mechanic.
