OH by the way when you tell me think of a game that is as big or bigger then Oblivion
1) Not all the bugfixes are minor, by far. I suggest you reading the complete changelog before talking out of ignorance. And still, even IF they were minor, 2k annoyances sure are a serious lot of annoyances.
Besides, it also depends of the gameplay of the player. Halo-like players who rush to complete quests and doesn't care much about anything but hacking&slashing will surely run and notice much less bugs than roleplayers.
And 2) Size is no excuse for leaving bugs unfixed. Bethesda had (and has) a nice team and resources in order to fix those bugs. They just have to use them.