Have these Underlanders ever, since Mr. Sandwich took them below, had a non-prophecy day? It seems to me that Gregor is always hopping down the air shaft to go fufill some underground prophecy and no one bats an eye (or eyes a bat, ha ha ha), like prophecy-fulfilling is a daily thing, something everyone knows about and engages in from birth. Like breathing and eating. It makes me think that Sandwich and others scheduled every day from now until the series ends with prophecy-doing.
Getting Gregor to the Underland is beginning to feel contrived, the prophecies even more so. I think it would have been easier to just lump all the cryptic rhymes together to form one quest that could take place over the course of the many books.
These are beginning to take on the Harry Potter rhythm I often find so frustrating: Start at home where things are rough (in Gregor's case, it's near-poverty and a missing parent, rather than living in a closet in the home of gluttonous relatives), go to a magical place, do something great, then return home. Next book, start again.
I will keep listening to the series; I like the idea. I like the cockroaches. And, amazingly enough, Gregor is growing and maturing. There's enough there that makes me want to continue the story, but the individual books are becoming harder and harder for me to follow without a lot of heavy sighing.