Fair enough. I haven't read them for a while so I'm only going on a 4 year old impression. I have a clear mental image of his world, which doesn't necessarily equate to clear world building skills. Perhaps it was due to the vagueness you mention - it allows the reader to extrapolate the details?

Another nice example of providing a clear concept of a world is Guy Gavriel Kay in A Song for Arbonne. He did a good job of giving his world (just 4 nations) a clear character and a sense of reality. Again, I can't say anything about the actual accuracy of his world, but it gave the impression of being real and detailed.