I'd hardly call Oblivion or FO3 "unfinished." Most of the bugs (other than that fucking POS engine crashing all the time) were minor and could be ignored.
But design decisions like console UI and shitty leveling mechanics got fixed by the community in hardly any time whatsoever. I think the first mod that did something about the leveling came out about 10 days after the game was released. (for Oblivion.)