I agree. Instead of leaving the book so lean, sparse and tantalizing, they should have had the decency to at least fill out the campaign models a bit more. If WOTC is hoping to generate enough interest so that they could justify releasing separate books for the campaign as they did for Urban Arcana, Shadow Chasers and Apocalypse, they are mistaken.
Still, as a completist, I am glad they came up with the book, if only to complete the Trilogy. I wager the team that created the book is more inclined to d20 Future than the Past.