Guild Wars 2

As the subject says, i always loved to have some kind of bestiary in Guild Wars since i love bestiaries in general, and since you have the Mission Books and Signets of Capture in the original game i always thought that would be a great way to capture/draw/defeat (or any other method) one or more foes and add them to your Bestiary Book,
which will then give you a bit of lore, possible weaknesses and what would be perfect a 3D model to zoom and rotate or otherwise an awesome sketch of the creature you logged/captured.

I know we have the wiki for most information, so it might never be implemented, since it will surely spend resources used on more demanding features?
But still it is fun to talk about.

I agree it would be a nice addition, but only if they added alot of gameplay around it.

What I mean is, as you suggested, missions.

To be honest, they should first implement Skill Hunting back into the game.
I also made a suggestion (check my signature Expansion Concepts and Skill Variety) that would greatly combine with the concept of Bestiary.

Essentially, giving all Skills a few possible enhancements (you pick 1 at a time, kind of like Diablo 3), and to obtain these enhancements, you must defeat specific creatures scattered throughout the world (no hints, though).
So you’d really want to defeat all of them to “inspire you” to discover better ways to use your skills.