3. Improved User Interface
Firstly, you will able to categorise items using sortable bags. So you could have one bag for equipment, another for consumables etc. Quest items will no longer appear in your inventory, but instead will be stored in a separate quest UI. Collectables such as Heirlooms and Toys will also now appear in a separate inventory instead of cluttering your bag and/or bank, and, once unlocked, will be instantly accessible for all characters on your account. My own bag is currently an unmitigated mess, and these changes are certainly going to help me out. They are also fine tuning the quest log a bit, in that the distinction between a main story quest and a side quest will be clear. This means that you won't accidentally miss out on some key story elements. It doesn't sound like much of a big deal, but it's little things like these which are going to have a huge positive overall impact on playing the game.