The worst RPG i've ever played is Sacred 2. It made absolutely no sense. Here are a couple of samples: In one quest, you have to defend this farm from wolves, then go adn clear out the wolves' lair, but when you get back, the farmer turns randomly into a werewolf. worst of all, i think his name was Jacob. In another, you have to hunt down an alien. You talk to this one guard who claims it ruined his life, investigate crop circles, then, at the conclusion, fight one of those aliens from AVP. Seriously?!? In one more quest, you have to find and return rock instruments to this heavy metal band. No joke. Meanwhile, the guy who gave you the quest just stands there and tells you about heavy metal and instruments and stuff while you kill things. When you go to get the drumsticks from this lich, the lich says something along the lines of, "You mortals must die!!! Wait, you're that guy from the band! I love you guys! If i'd have known these were yours i never would've stole them in the first place! Can you ever forgive me? I still get tickets to the concert, right?" And when you finally have everything, the game shows you a cutscene of a heavy metal concert. It does. And when that's over, you get the instruments as weapons. There's like 600 quests in that game and only about 20 are serious or make any sense. The graphics suck, the combat sucks (push this button, push it again 26 more times, push a different button, push the first button 42 more times, etc.), the co-op sucks, the voice acting (when there is any) sucks, and the whole thing is full of bugs. I don't think they ever beta-tested it. This has gotta be the worst game i ever played.
P.S. I know what you're talking about, Damar, about Oblivion and Fallout 3, but they were still good in terms of the sheer size of the game. It takes about 100 hours to go through all the quests and find all the collectibles, legendary weapons, etc. Plus it's still fun to nuke raiders eight times at once with the experimental MIRV :P.