The nature of Biblical prophecy?

In his commentary on Isaiah, Childs notes the trouble chapter 46 has caused interpreters. The fall of Babylon through Cyrus in 539 did not follow historically the predictions of Isaiah. The great city was not levelled, nor were the Babylonian gods dishonored and replaced. A traditional response, which works on a theory of direct historical referentiality, claimed that the events must be directed to the later conquest by Xerxes. Redaction critics, on the other hand, attempt to isolate later literary levels that developed in an attempt to actualize the original prophecy, especially in the light of its failure to materialize as predicted.

Childs rejects both approaches and claims we need to do justice to "the unique nature of a prophetic proclamation" (361). But just what is this nature? I quote part of his answer below. It's dense and challenging. I'd appreciate feedback on his claims, either in the form of an explanation, a challenge or an affirmation of his point.

Biblical prophecy is not simply a description of a coming historical event made in advance, shortly to be visible to all. Rather, Isaianic prophecy interprets the effects of God's entrance into human history. It embraces a different dimension of reality, which only in part coheres with empirical history. The eschatological appeal of God's rule involves a vision of divine intervention that indeed enters human history, but is not exhausted by any one moment. The quality of God's salvific presence is not limited to one specific event in time and space, but embraces the whole of God's announced purpose for creation, which moves toward consummation. The nature of correspondence between word and event can only be measured in terms of this ongoing divine plan toward ultimate restoration of God's creation. Prophecy thus speaks of a quality of future event. It is not a clairvoyant projection of the events within the unredeemed experience of human history (362).

These comments should be compared to related ones by Jörg Jeremias. Check out too the article by Ronald Clements on the subject of prophecy and fulfillment. I hope to post on this at some point in more detail.

Update: See Wilhelm Vischer's take on the issue, which sounds close to Childs.