The world is expected to be more dense, decreasing the overall size in order to fill it with life. I expect a more 2D traditional Zelda approach where you must traverse the vast world and fight your way to the Temples and Dungeons as opposed to simply riding your horse/bird to the next location. In the overworld, I want to see life. I want tons of enemies present throughout a number of spaces filled with new areas and secrets to explore. I want NPCs walking certain paths between a number of towns and villages. I want to feel like I'm in Hyrule, surrounded by life, surrounded by threat.
Sidequests are a must throughout the story, particularly if the NPCs involved correlate to the main quest, similarly to Majora's Mask. I don't merely want these interactions to be specific to Skyloft, as there is a world filled with quite a number of civilized races beneath the clouds, including Gorons, Humans, Zoras, and the Sheikah. Apparently, there is no "main field" in Skyward Sword, so elements like this finally have a chance to bring themselves to fruition, particularly after the five years Nintendo have invested in making this game perfect.