I only have one problem with Adam being a metaphor for mankind. He is listed in the genealogies (If I remember correctly) If he is just a metaphor, then at what point do the genealogies become literal?
That is quite a slippery slope.
SO far I am of the opinion that there was a literal Adam, though there were other hominids, maybe even self aware (as Elephants have proven to be) but that God "breathed" on Adam and thus began the impartation of the soul, and moral responsibility.
Thoughts?