- Something BIG that's been hiding or lurking for a while. I think the story behind the Titans, Old Gods and where the Legion has been is due. Kil'Jaeden is still alive and Sargeras is still out there, and Queen Azshara and N'zoth still have yet to be seen. Also, Neptulon.
-Class "niche"/uniqueness better reinforced. I'd at the very least like to see some more interesting talents and I firmly believe that not all classes should have the "utility tier/CC tier/damage tier/mobility tier" standard going on. (As long a uniqueness reinforcement doesn't affect your role in raids, obviously.)
-Better lore for races. More Draenei, Worgen, Gnome, Goblin, Tauren and Human development plz.
-Trimming of the keybinds. It's all cool and whatever that playing a class takes skill because of how you handle your spellbook/items/macros, but it's at that point where there are so many skills in the game that they kind of become an afterthought or aren't a satisfying button to push.
-At least one new dungeon per patch. It may be easier to develop scenarios, but I just miss dungeons being relevant throughout the whole expac.
Some other things that have already been said such as item squish, heroic dungeons feeling like a heroic dungeon (since there is much more content than ever to gear up early expac), updated models, racials overhaul.