I have to think that editing down to the required page count has something to do with this as well, as the bare bones are fine, but i seems that there's a lot of meat that appears to have been cut. It's not terrible, but the book could definitely have used a few more pages to flesh out things like this.
(I'm planning on fleshing out things a bit more by having the portals appear further away from the pices, which will allow for some more setting flavor before getting to the main dungeon for each chapter. So the party will have to travel a bit through the Underdark, will need to travel a bit on an actual functioning Spelljammer ship, etc. I'm having to research a bit on Rel Astra since it's the nearest city to the Greyhawk dungeon. They would obviously have not been able to fit such preludes in the product for space reasons.)