Personally I would like to see small stuff like:
Sword usage (So I can equip Thunderfury :P but also so enhancement shamans have a wider range of weapons to use). There are som shamans in the lore who use swords so I don't see why not.
More races. I would like to see Blood elfs and maybe Night elfs for Alliance. I know it doesn't really make sense but I really want to change my orc to a BE. Best race IMO (after trolls).
If they were to implent a fourth spec my suggestions are:
Earthwarden: Use the power of the earth to imbue your armor and weapons. (Tank)
Elemental binder: Calls forth powerful elemental allies to aid you in combat. (Kinda like a beastmaster hunter but with melee attacks and lots of pets)
(no name yet): A elemental master of bows/guns. You bind your arrows with the elements and blast your foes.
What's your suggestions?