when I finished the major questlines in oblivion I liked to just enter the game and do stuff beside quests and exploring! What possibilities did we have in oblivion? one day I stole the keys to every house in bruma, one day i made friends with every guard in the imperial city...
but what if we had little optional quests/jobs like praying to the nightmother once a week or maybe fight in the arena, just something to do with some purpose when you just want to experience the atmosphere of the game?
and please don't answer with "go play the sims" or "you are a fighter just kill some dragons" these little jobs could be optional quest which repeat themselves once a day or week.