I'm in total agreement here. Yet the line of continuity between all these texts is that they have been used religiously by a particular community of faith throughout its history as a testimony and response to its God. Diversity and even logical contradictions don't exclude the possibility that there is one God behind it all, revealing himself to and guiding his people. Which is why, I think, Childs talks of the “substance” of the Bible as being “dynamic,” i.e. God in relationship in history. The central formulae of both Jewish and Christian faith are narrative in nature, rather than abstract description. Irenaeus, for example, spoke of a movement from “creation to incarnation to consummation.” The task of exegesis, an exegesis which wants to really get to the subject matter of the Bible, is to read each text both in its integrity as well as in relation to this (or another) broader picture. Christians believe in the Irenaen one. Others have other “meta narratives” by which to combine the parts into a whole (e.g. Marxist, existentialist, evolutionary, etc.).
I guess so, but it's not arbitrary. It's a matter of subjectivity within boundaries guided, hopefully, by the Holy Spirit.