The problem with oblivions world was that it was too boring and uninteresting, Skyrim will look awesome and if it is the same size as oblivion, it will be a beautiful gaming experience.
One man's meat is another man's poison.
I think Skyrim will concentrate on packing a wallop into every square meter and be big on fighting - I'll expect danger everywhere and will need a good sword right off the bat.
I think Oblivion's world is the most interesting gamescape I have played with to date.
To me size DOES matter. I would like a world that really took a realtime day to cross it.
Lots of small adventures in a environment that was full of wildlife right down to birds and bugs.
Keep the main quest and all the boss NPCs in the central city so players who want to whiz thru the game don't have to go anywhere to beat it and spread optional quests in a huge game world full of interesting situations such as helping the old lady get rid of spiders in her cellar and clearing out the wicked goblins from the local kwama mine.
A Christmas world to sleigh thru wrapped up in furs and listening to the ice crack as the reindeer race me across a frozen lake under crystal stars twinkling above the mountain tops with the aurora borealis flashing curtains of purplely green lights across the sky. " Onward Blitzen!".