Three years ago, I read this article by Annalee Newitz on sexual dimorphism in WoW, promptly filing it away in my head as one of those interesting quirks about the game and games in general. What really struck me at the time were the alpha pictures of trolls and tauren. While I like the current tauren female model, I'm not terribly enamored of troll ladies, if only because 95 percent of them (not an actual statistic) seem to choose the same blandly "pretty" face. Alpha troll women seemed to share a lot more of the troll male's features, with more pronounced tusks, sharper profiles and more of a hunch like the men. In general, I found these alpha models fascinating.
Also interesting to note was that this trend goes both ways: when blood elves debuted, the males were much closer to the females and were beefed up in The Burning Crusade beta. As Annalee Newitz pointed out, the other race that debuted in BC, the draenei, are extremely dimorphic; males are bigger and more massively muscular than orcs, while their females are far less mesomorphic. What interested me, at least so far as the tauren and troll model changes went, is that players complained that the tauren and troll women weren't to their liking, which most likely had an influence on the design of draenei and blood elves.
Now, with Cataclysm, we have two new races to consider. How do the worgen and goblins stack up on the dimorphism scale?