What I would have liked was some exploration, something that Wizards seems exceptionally bad at including in their recent adventures. You can have empty areas if they have things to puzzle and intrigue the characters.
I wholeheartedly agree with this, and thought the same thing when looking over the new 4e mods.
http://www.enworld.org/forum/general-rpg-discussion/244799-old-school-modules-space.html
Non-encounter space (e.g., neither a combat or skill-heavy area) can still be interesting by changing the pace, revealing something of the world, or foreshadowing future events.