in terms of strictly races included with expansions? i know when cata released and Goblins and Worgen became playable, i still to this day dont have a worgen (never was into vampires/werewolves) so worgen didnt interest me in the slightest. Goblins, i was like yay, i can have my squirt sized warrior now but, it wasnt a major selling point for me either.
then MoP was released, and pandaren which i was really excited for and enjoyed immensely, and pretty much made every new alt a Pandaren, so yes MoP did offer a selling point in that race.
WoD does not bother me and im actually more excited over the updated models than any other possible *new* race. i doubt they could have added a race that i would have been very excited about at this point, mainly because i feel WoW has enough races for now.
so i guess all things really are relative. sometimes its a selling point, others its not.