I think that the NDE aspect of Dr. Alexander's book is secondary... What his book really does is offer evidence that consciousness can thrive outside the physical body. This is both more important than--and not as easy as--concocting an elaborate narrative of "heaven," because it flies in the face of mainstream scientific thought of the past century or so.
That's probably why there has been such a visceral reaction to the book among the mainstream. The mainstream will allow the kooks in the paranormal gallery to channel various non-physical entities that say this, but it's quite another thing for an established scientist to promote it. It's a very subversive concept that, if carried to its logical extreme, undermines much of our current power structure.
I hope that Eben Alexander continues to expound on the information that he received during his seven days out of body. In the meantime, I plan to read the book carefully several more times. I think that his book can serve as a touchstone of sorts to what I am leaning toward... a physics of non-physical state.