I don’t think I would have got round to reading GAME OF THRONES if I hadn’t seen the HBO TV series, but I’m glad I did. The series is excellent and is an attractive way to enter the world that G.R.R. Martin has built. The world-building is wonder-inspiring, and the world built is not just some disguised variant of Tolkien’s world. So I think the biggest effort the reader must make is in the first part of the book, as the world is slowly set up from within. Ted Friedman thinks that there is a significant turn in the collective psyche from science-fiction to fantasy as ways of dealing with the imaginative and affective aspects of our relation to the world (here).
The return to a pre-enlightenment world has something in common with the progress on to a post-enlightenment world (the singularity, or Clarke’s Third Law: “any sufficiently advanced technology is indistinguishable from magic”). Rationalism is not enough, to speak to our contemporary productive unconscious, more is needed. Christian moralism is not enough either. GoT is not set in a world of Christian values, and the narrative voice and structure are not Christian.
Polytheism of different sorts is the religious context, and is an important part of personalities and outlooks. The characters in GoT are not demarcated out into good and evil, with only a tiny amount of ambiguity. They are combinations of light and shadow, though the proportions do vary. The game of thrones itself is not one of establishing the rightful hereditary and noble king on the throne after vanquishing the Dark Lord, it is a game of power strategies and Realpolitik, with no final legitimacy.
So I would argue that along with the shift in our culture from an SF metaphorics to a fantasy one, GoT illustrates and embodies the shift from a Christian monotheistic perception with its dualistic vision to a polytheistic perception with multiple points of view each having a certain degree of validity, and where dark and light are not separate and opposing instances (there is no axis of Evil in the human realm), but are distributed throughout the opposing sides. (The overwhelmingly evil Others exist, but their background presence does not transform the human realm into the site of cristallisation of good).