Mail. This one little thing in WoW really has made items less of an albatross around my neck. I can chuck an item, keep it, or sent it to someone who might need it. No more hanging on to bags full of equipment and items, wondering when I’ll meet someone to hand it off to them. Swing by an inn and drop it in the mail. I think it’s the little improvements that can make a game enjoyable versus tolerable.
I also find the crafting aspect of WoW to be very easy to deal with. The interface makes fabrication very smooth and easy to work with. You aren’t fumbling with buttons or items or anything. Most of WoW has this same interface smoothness that makes the game very easy to work with. I do think that the screen real estate is the most limiting aspect of the interface and Blizzard did not want to clutter it up with more buttons. But, I would expect that most people will add user interface modifications to change that.