That's the thing, bigger is not better. In fact, it usually brings the opposite since as the scope of your game expands, your ideas lose focus. I was really refreshed by the tightness of Dark Souls when I played it, since it's an open world game that really felt like everything in the world was interesting and worth exploring. It wasn't gigantic like Skyrim, but it emphasized quality over quantity. I've felt the GTA games going the other direction since III, and I've played all of them other than the Episodes from Liberty City (I just ordered a PS3 disc of this actually) and Vice City Stories, so I really need something fresh to keep me interested.
I always scratch my head at this argument, because i think it's an oversimplification of the issue.
Bigger is not always better, we agree on that, but the opposite is also untrue, not everything has to go for the laser focus experience.
An empty space has very much a time and a place in the pacing of an open world game, a game which is meant to sell you on the vastness and mystery of a land, such as Shadow of the Colossus, would be total crap if it removed the empty spaces to keep the Dark Soul's density and pacing.
Much in the same way, if you create a desert or a forest that is meant to convey a sense of disorientation, you can't put it directly attached to the city with an overload of breadcrumbs connecting the two.
Empty space in an open world is necessary to convey a certain type of pacing, even in the designing of a map.
When you travel from "coast to coast" in an Elder Scrolls, you're supposed to feel like you've crossed a nation, it has got to have some empty space without enemies, loot and other crap distracting you.
It's a very different goal than something like Dark Souls, infact.
I would argue that Skyrim doesn't have ENOUGH empty spaces, since every two steps a were-rabbit is out to get you.
Speaking of GTA, more over, the huge map has even more sense, since they're trying to sell 3 different characters that should live far apart from each other (metaphorically and geographically) with the addendum of needing enough space to give planes some sense.
