The Blighted Bestiary is more than just a collection of potential foes. It provides a theme-oriented array of villains to challenge characters of all levels. These foes provide for many types of challenges. Creatures like the Shelldrag provide the typical hack-and-slash challenge, while Blaze Shrikes require a bit more strategy to defeat without getting yourself injured. The Semyad are the most intriguing of the opponents. Although they are not specific creatures but a template to be applied to other characters, entire campaigns could be built around rooting out networks of Semyad who have woven their ways into society.
My only criticism is that many of the creatures do require work by the Game Master to fit into a campaign or adventure. Fendracs, for example, don't specify how large the packs typically are.
Although the adventure hooks do offer angles for Game Masters to fit the creatures into any campaign, it seems that they would be best suited to rounding out a campaign against the Blight Elves themselves. But, all-in-all The Blighted Bestiary successfully conveys the dark, depressing nature of the Blight Elves.