Sexual Dimorphism in World of Warcraft

Game designer-in-training Andrea Rubenstein has just published a great article about fantasy bodies in MMOs, focusing in particular on sexual dimorphism in World of Warcraft. She points out the bizarre differences between male and females of nonhuman races, asking whether it makes any kind of sense that female Draenei would be so small in comparison to their male counterparts:

The race with perhaps the starkest contrast between the sexes would be the Draenei. What stands out first about the sexes is that the male is massive: tall with unnaturally large muscles and equally large hooves.
Given this build, it would not be unreasonable to expect the female of the species to be similar, but instead her slim features are closer to that of the female Blood Elf than to the male of her own species.
Female orcs share the same problem, although they are clearly the most muscular women in the game, perhaps apart from Tauren women. There is also a marked difference in the non-human markers such as tails and ears. The same can be found with the trolls – with the males having visibly large tusks while the females are only allowed ones so small that they often fail to show up in screenshots, not to mention the complete difference in posture – and the Tauren as well, as the males get horns and facial piercings while the females do not (Fig. 7).

She points out that these female bodies embody the "feminine ideal" of the supermodel, which seems a rather out-of-place aesthetic in a world of monsters. Supermodelly Taurens wouldn't be so odd if gamers had the choice to make their girl creatures big and muscley, but they don't. Even if you wanted to have a female troll with tusks, you couldn't. Which seems especially bizarre given that this game is supposed to be all about fantasy, and turning yourself into whatever you want to be. Apparently, the designers of WoW also thought the extreme dimorphism was weird.

Originally, in the Alpha version, female Taurens and trolls were a lot bigger and had horns.

But fans complained:

In the Alpha version of the game, races such as the Tauren and the trolls had more similarity between genders than difference: facial structure, body shape, posture, and even choice of accessories were more similar than not (Fig. 8). Apparently there were many complaints about the women of both races being “ugly” and so the developers changed them into their current incarnations.

Read the rest of Rubenstein's witty essay for an original, subversive take on WoW culture. I'd love to get a biologist's take on all this. What natural conditions could possibly cause such strong sexual dimorphism to take place in WoW?