It's a cleverly crafted prologue, good balance between the conversation in which Lynch shows off his brand of clever dialogue and the flashbacks in which he rapidly sketches the particularly merciless city of Camorr and the character of Locke as a young boy. The Elderglass is intriguing as well, as Nate said.
The Black Whisper thing seemed rather exaggerated, though - a plague that kills all adults it infects? Even with such radical quarantine measures, it's hard to see how a medieval city could survive even one outbreak of such a plague, nevermind enough of them that the Thiefmaker can consider it his "favourite" plague. And as it turns out it wasn't even needed, as Locke's already an orphan anyhow... I suppose looking for realism even by fantasy standards in this book would be missing the point, but what can I say, I'm a critic clearly.
I've yet to read and see the Godfather, so I'm kind of curious - are all the references (to begin with "Camorr" itself) to the mafia in general, or to the Godfather in particular?