-The first and most important reason is the "amount of time spent in an area". In Fallout 3 there was a town called megaton. In megaton there was stuff to do and interesting people to meet, these people often gave quest for you to do and kept you busy. On top of that near megaton there was a school that was not a quest but felt like one. Also there was a supermarket to explore. So the point is, in just that small area around megaton you spend hours playing without really venturing too far. So when you start to really explore the world it seems bigger because you spend a lot of time in each location. So how it differs from Oblivion is the dungeons in Oblivion are very straight forward and dont really keep you there for long. Along with other locations. So I believe in Skyrim areas will be packed with content keeping you in a small area for longer.
- Another reason is "more unique/interesting locations". So both Pete Hines and Todd Howard has stated that Skyrim has more content than Oblivion. So From what we saw in the gameplay videos the locations looked very interesting. In riverwood people are doing there daily jobs, kids playing with the dogs, interesting conversations. The same could be said with the dungeons, in Bleak Falls Barrow you could just see the level of detail from opened roofs that brings in snow, to overgrown vines and plants, to waterstreams and waterfalls forming, to puzzles and then some. Just that one dungeon seems really interesting. I doubt bethesda would stop there.
- The last reason I can think of is "more content". Now I'm not sure what this means but I know that Skyrim will definately not feel as empty as Oblivion.
So with that said tell me if you agree or disagree.