I'd like to see a bestiary in-game. After killing 1 (5, 10, more?) of an enemy it'll appear in the list. Ideally, the page for each enemy would give its stats (e.g., health, mana, drops). It would also include a cute picture of the 3d model for the enemy.
So yeah, this isn't the most important thing in the world. But adding this sometime would be really cool.
Then make achievements for filling it up.
Guild Founder of The Golden Horde
Zshmaendal - Level 45 Prophet | Superfluous - Level 35 Warrior | Ulysses - Level 13 Ranger
Louis - Level 8 Warrior | Ephemeral - Level 12 Assassin | Connotation - Level 8 Mage
Crystal Cutting - 9 | Fishing - 10 | Forestry - 10 | Skinning - 8 | Farming - 19 | Foraging - 28 | Prospecting - 16
Alchemy - 36 | Cooking - 11 | Leatherworking - 4 | Weaponsmithing - 5 | Armorsmithing - 7 | Jewelry - 6 | Tailoring - 16