This is every Stephenson book. Snowcrash, Cryptonomicon, Anathem, and The Diamond Age also fall victim to similar problems. He is a fantastic world-builder, but

This is every Stephenson book. Snowcrash, Cryptonomicon, Anathem, and The Diamond Age also fall victim to similar problems. He is a fantastic world-builder, but eventually he runs out of paper and needs to make things resolve, and the pacing falls apart. Incidentally, GoT is suffering badly from the same problem.