Disappointing, as much as I love Vimes. Hit the moral points too hard, prose sometimes hard to parse, goblin religion went nowhere, and, ohdear, the white-liberal-well-meaningness of the race analogies! Species as race is inherently problematic, but it gets even more so when your downtrodden goblins need the help of the white human dude, (two) ladies bountiful, and the potentially supernatural. Also when their existence as sapient beings depends upon them being able to perform civilization as defined by humans. Some of Angua's reflections point towards the problems with assimilation, but that goes nowhere.
The goblins are mostly similar to indigenous peoples, but there were a few things that reminded me of blood libel.