Thumbs up for bestiary. I could see myself putting in countless hours just trying to fill up the pages.
When it comes to loot, I think it should be more like Castlevania's bestiary (or atleast thats the first game that comes to mind), where it shows the number of potential loot a monster can drop (Represented as "-------") and when the actual item drops, it gets added that list of loot. This keeps the bestiary from being a bit less abusive imo.