Like I said, this expansion is young and we're only at the first patch. I agree with you on that point : I would like to see all Alliance races get their time in the light in future patches. Especially Night Elves, since they are the biggest force for the Alliance in Kalimdor and that most of the Horde is on that continent (ok, I admit I also love Night Elf lore). However, if they want to show the Alliance as a unified force (considering what Wrathion says about the Alliance), they must first show Varian's qualities as a unifying leader, leading several nations to reach a common goal.
So far, I think this expansion is full of promises for good story developpement.