Expansive, but stumbles with creativity and innovation.
If only all of this were true.
Oblivion is indeed expansive, but it's in no way innovative, state-of-the-art, or wholly creative. It's hard to become immersed when many things in the game world lack shadows, even at the highest settings and it's hard to become immersed when every dungeon looks exactly like the one before it. Oblivion's world suffers from an unhealthy dose of repetitiveness.
The world is not the only sufferer of this repetitiveness. The quest design, the characters, the voice acting, and the general gameplay all have a slow and dumbed down feel to them; you're constantly running from point A to point B, slashing the same monster types and looting the same chest types. If there's any creativity in Oblivion, it's hard to find.
Even the claims of Oblivion being a character sandbox fall short. Hours into the game, nearly finished with the main quest, hours spent roaming the countryside for extra goodies - and my character feels just like he did when he first started. There's nothing to be found in Oblivion that truly makes you feel powerful.
Graphics - Visuals are impressive, but only if you place aside that fact that nothing static casts a shadow and that anything at a distance looks horrible; textures are repeated to the point where everything looks the same; art direction is asleep.
Audio - Character voices throughout the game are voiced by the same five or so people; Sean Bean sounds like he was bored out of his mind; Patrick Stewart was drugged into doing this game because he sounds catatonic.
Gameplay - Melee characters feel sluggish, magic characters feel downright boring; the same dungeons all over the place; bland mission and quest design; interface is convoluted and cramped.