The classes that have their own mounts are:
Paladins: they have these armored charger horses
Death Knights: they have the ebon blade steed and the skeletal gryphon flying mount
Warlocks: they have these fiery horses that can walk on water
Druids: they can fly on their own and their ground travel form can go to 100% speed with the glyph
Shamans: theyr spectral wolf form can go up to 100% speed with the glyph
Demon Hunters: they are a hero class so most probably theyl have their own mount
Now about the other classes
Mages: either a flying carpet specific for this class or an arcane steed
Hunters: a dragon styled mount where at level 40 it gains wings
Priests: angelic wings/ val'kyr transformation or something similar
Warriors: big armored pigs with weapons attached to their tusks/sides and a banner at the back, not the boar mounts that we have i mean acctual pigs butwith tusks
Monks: the Zen Flight should become an acctual spell and modified so it goes as fast as a real mount and can be used in both ground/air
Rogues: a spider mount where at level 40 it becomes armored spider
If you have better ideas post them here