Final Level: "Try To Stop Jack Of Blades"
Why It Sucked: Moral choices in games need to have consequences to actually be meaningful. At the end of Fable, you can either kill your sister and become "powerful," or ditch an awesome sword and get to keep your sister around. But either way, the game is over, and there's nothing else left to do. And why would your sister even tell you about the option where you kill her and become evil? What an Idiot.
How We Would End It: By giving players something to do with that badass sword and all that "power" (which manifests itself in the form of a pointless mask, by the way). How about making the arena re-playable, with different challenges and enemies? What kind of game has an arena that you can only challenge once?