For me I would be interested in exploring some of the characters' back story, such as Reaver and Theresa. I know there are books and snippets here and there but nothing concrete and 100% canon.
In further relation to the thread I think we have all unanimously decided, for the Fable franchise to continue we all need Lionhead to have a long think and take an in depth look at the last three games selecting the best bits.
Thankfully, as horrible as it sounds, a certain lead developer is no longer with the company, so we can hope for no more over hyping leading to disappointment. I’d rather live in ignorance, not knowing any elements going into the game so as not to be disappointed, as opposed to being promised the world and left unsatisfied.