What you are describing is a typical approach, Michael, so I understand it well. But let me propose to you a different perspective. It has often been said, that things are not true because they are in the Bible; they are in the Bible because they are true. The presumption is that the Bible will not contain untruths, because it is against the nature of God, the Spirit, and the writers to put untruths in scripture. Okay, maybe you agree with that.
Metaphor is true in the sense of what it is trying to convey, assuming that it portrays truth. A metaphor of untruth would not be true. In the case of animal story, we quickly understand that the conversation of the animals is supposed to represent something else, just like the parable of the father of the prodigal son represents God interacting with his children. From there on, the conversation makes sense.
Making Genesis one into a parable or metaphor, rather than a telling of events, is like making God represent God, and first man represent first man, and world, water, sun represent world, water, sun. Because there is not a transition to a metaphorical form, we cannot know what the point of the metaphor really might be.
While it is true that certain cultures use more symbolic language than others, or use language that is more “couched” in indirect language, possibly in order to reduce emotional conflict, this is more cultural than language based. Some backwoods cultures are incredibly subtle in their communication, but when you understand and are accustomed to their use, you realize it is only subtle for outsiders, and not at all subtle for those who speak such in a daily way. It is possible to be either very direct, or very subtle in English, as well; it depends on the user and the context and the culture. This is why some people are very insulted by language that other people do not even perceive as significant.
Your comment about Hebrews understanding an inaccurate account is possibly valid, but in some way misses the point that many EC argue that Genesis 1 was written the way it was (inaccurately) because the Hebrews would not have understood the science (present day knowledge of space, etc.). This is an invalid argument because if mere understanding is the criteria, then certainly they would not have been able to “understand” how man could be created from dust, or in fact how everything could be created so quickly, or how light could exist without the sun. Understanding or lack of understanding (in otherwords, historical culture) is not a valid argument for why Genesis is written the way it was.
Finally, what evidence do you have that they understood the creation stories as metaphorical? Why would they have a reason to do so, if they did not have knowledge of nature that would contradict the facts of this story?