I will likely be content with the content in the book, but what I would very much like to have is more NPCs, more beasts and more undead - specifically templates for making a variety of NPCs, beasts and monsters into various types of undead. There have been a number of zombie & skeleton templates posted on the forum, but are all ghasts, ghouls, ghosts, wights, wraiths and vampires the same? How about a Dire Beast template? How about a Lycan template?
I've taken a crack at a few of these myself, but some hard mechanics to model would be helpful.