Fable I: Great game. Could have been better with about 8 more months of development.
Fable II: Excellent game. I loved the gamepla mechanics, graphics, etc. How you leveled was wonderful. It could have used about 6-8 more months of development as far as character interactions and side quests go.
Fable III: I hated the level up system. Story was okay, not great. Graphics were on par or better than II. It just wasn't doing it for me. I liked how they vastly improved the building management systems. That was A. They could have gotten an A+ if they made it more accessible. The zooming back and forth to your "hideout" was also a bit lame. Decent game..not on par with the previous, but did have some good improvements.
Fable III.5: WTF.