I don't know that it will fail in terms of a train wreck, but i don't think the reputation of molyneux will help it. I never played the first fable but started on fable 2 and enjoyed it. After i heard the features and changes of Fable 3 i went out and bought it and have to say that i was disappointed, i still haven't finished it.
After i heard that Molyneux straight out lied a number of times it turned me off any further game of his or his company. Even if Fable 4 is being released in the future, i have no intention of buying it. At least until friends tell me what they thought. I'm guessing that many people will do the same with The Journey. Lionhead really need to rebuild consumer trust.