Peter Molyneux, the original creator of Fable, has called Fable III a "trainwreck". While speaking to Develop Molyneux said:
"I think Fable II was a step in the right direction. I think Fable III was a trainwreck. It was built to be much bigger than what it was constrained to be and eventually ended up as.
If I had my time again, I’d take the advances we made from Fable 1 to Fable II, I’d make the same advances from Fable II to Fable III and spend another entire year working on Fable III. But would it be that perfect gem that’s in my mind? No.”
Fable III was, in my opinion, the worst of the "core" Fable games. Molyneux has always been very ambitious with his hopes for his games, as he himself is the first to admit:
“The trouble with me is I do this stupid thing, and I always do it, where I start talking in an excited way about what I’m working on before I’m finished,”
I've met Peter Molyneux a few times, and you can see he's genuinely excited about the games he talks about, so I believe him when he says he doesn't mean to mislead people.