Having things like Spellmaking, the achievement of actually working your way up through the Mage's Guild, etc, are what make Oblivion steak compared to Skyrim.
Oh, seriously? Really? Oblivion? Look, I thought Oblivion was great too, but five minutes of Skyrim convinced me Oblivion couldn't hold a candle. Better voice acting, better story, and yeah, better quests. I liked the Mage's Guild and Fighter's Guild quests well enough in Oblivion, but the Companions I find far more interesting. Spellmaking was neat enough, but you could make things overpowered too easily with it. I wouldn't object to it being added back to Skyrim, but still, it just doesn't strike me as the horrible, horrible loss that some seem to consider it.
Just the amazing art direction in Skyrim places it head and shoulders above Oblivion.




I loved the look of that Werewolf skill tree too! I really wanted one for them and Vampires. That would add so many more options!