There are surprising amounts of “lore nerds” out there in the WoW population, and something like a Tome of Knowledge could only help make even more of them. At the same time, it would give roleplayers a sure-fire reference material right there in the game, any time they wanted to know how to roleplay something, the lore information in the Tome would give them a lot of good guidance, either through facts, or through short stories that help illustrate character and context better than anything else in the game.
All the World’s a Stage: How to bring Warhammer’s “Tome of Knowledge” to WoW