To be fair, games like LOTRO don't actually have 30k of usable zone space, not even close. I haven't seen much about Guild Wars: Nightfall, but it's probably the same - not actually space you can walk around in. Asheron's Call is absolutely huge though, I've spent an entire day just running across the map in the past, even at crazy fast run speed it can take a while, so running around the entire world would take an inordinate amount of time.
Even barely counts, it's huge but it's space. It's an artificial inflation of size since you travel most anywhere jumping from point to point, and the planets, at least before dust, were just there for looks. So you aren't seeing much more than the same model planets and black emptiness.