I’ve never had a problem with the idea that the opening chapters of Genesis, which I re-read just the other day, are to be read in a way alternately described as “myth,” “legend,” “metaphor,” “saga” or what have you. Moreover, I think reading Genesis in this way is fully compatible with as robust a theory of biblical inspiration as you care to assert. There’s no contradiction that I can see between saying the Bible is inspired and saying that each book has to be read according to the conventions of the genre(s) it exemplifies.
In the case of Genesis, I’m perfectly comfortable with the common view that the creation story is more about disclosing God as creator of the universe, and humankind’s special place as the imago dei than it is a literal account of the mechanics of how the universe and life came into existence. In other words, there’s no reason to reject the view that human beings evolved from less developed forms of life in order to maintain the truth of the creation accounts.

However, what I’ve never seen resolved to my satisfaction is the role of the Fall in a post-evolutionary understanding of human origins. It’s difficult to square an evolutionary account of human origins with the idea that humanitiy’s original state was one of blessedness from which they fell into a state of sin. As far as evolutionary history can tell us, there’s no evidence for such a radical break in human pre-history. And there was almost certainly no period when human beings didn’t suffer death, disease, and the other afflictions mortal flesh is heir to.
Simply dispensing with the idea of the Fall hasn’t seemed viable to most Christians, not least becasue it would seem to have major ramifications in Atonement doctrine and responses to the problem of evil, among other things. So there have been a number of different attempts to re-think the Fall in the context of an evolutionary worldview. For instance, one might think of the Fall as describing something that each of us experiences individually, or a sort of ahistorical description of the “human condition” (see, e.g. Reinhold Niebuhr’s seminal Gifford Lectures The Nature and Destiny of Man). One problem with this view is that it has a tendency to make sin a constituent part of human nature or creation or finitude as such, which seems to compromise the goodness of God’s creation.
Another move has been to adopt what, for lack of a better term, I’ll call a “neo-Irenaean” view. Irenaeus, it appears, held that humankind was not created in a kind of preternatural state of power, wisdom, and innocence. Instead, he thought Adam and Eve were more like undeveloped children and the Fall, rather than being a cosmic catastrophe, consisted of humanity gettting off track from the path God intended for them. This has obvious similarities to the evolutionary view in that it sees humanity as starting out from an undeveloped state, rather than one of what seems to us to be superhuman blessedness. On the other hand, it may at times tend to a naively Pelagian view of freedom and to blunt the seriousness of sin, which may partly account for Irenaeus’s view that the Incarnation would’ve happened even if humanity hadn’t sinned.
So, any thoughts? Do you think of the Fall as a historical event (even if the Genesis account isn’t to be read as literal history)? Is it a metaphor? Something in between?