I finished it as well for the first time, but I found the appendices more interesting. If silmarillion is more of the same, sign me up.

In asoiaf, for me, the nihilism comes out of the realism in the events of the story, just like the randomness of real life, which makes me think there isnt anything behind the scenes. Things just play out regardless and you can never expect a happy ending that doesn't get paired with the most evil of things.

I was thinking more along the lines of tone. Like brutality of song of ice and fire or Bakker's Second Apocalypse. I find Abercrombie more cynical and darkly humorous

I think "nihilistic" is a little much. He's not that dark of an author. Reading the first trilogy, I find he does pull some of his punches. There were some places he could have gone, but didn't. In the end, I felt the tone was YAish with R rated violence.