Well, goblins may well be the least dimorphic race in WoW, or at least a contender. (Gnomes aren't terribly dimorphic either, so it may be as simple as a consequence of geometry.) Male and female goblins certainly are distinct from one another in their playable incarnation, with males having slightly more pronounced features and females being slightly taller.
While there has clearly been an effort to make the goblin female appealing visually, it hasn't occurred as a result of highly altering her body type to be very distinct from that of the male. They are both short, slight beings. There's no major discontinuity between the men and the women when it comes to goblins. Goblins are, therefore, a race lacking in a strong component of sexual dimorphism, which suits a people who are such experts at negotiation and commerce.
How, therefore, did our Gilnean friends come out of their curse? Well, since worgen were once human, we're already talking about a fairly dimorphic race in WoW. All human males, from the mightiest warrior to the warlock and wizard, are built like brick outhouses, as my father used to say. (He didn't say "outhouse," but you can understand why I made the substitution.) But do worgen maintain the dimorphism of their parent race?
I wouldn't say so. It's not that they maintain it -- it's that they take it as a foundation and go wild with it. One of the interesting aspects of World of Warcraft is that many of the males crouch; worgen are no exception to this trend, although they're the first Alliance race to do so. Orcs, tauren, trolls and now goblins all have between a slight and severe crouch or hunch to their posture in the males. Tauren females are taller than tauren males unless you count the pronounced hump on the male's backs; the troll females stand generally taller than the males, save for the rare moments when the males straighten all the way from their extremely severe crouching posture. Worgen are similar in this regard.
As can be easily seen in the picture above (including the feet this time), a worgen male is slightly shorter than a worgen female due to this extreme hunch, but almost twice as wide. The body type of a worgen female is nearly as slender compared to the make as the draenei but, like a tauren, is taller than the male due to posture issues. So worgen fall somewhere to the far extreme for sexual dimorphism for playable races, somewhere between draenei and tauren/trolls.
Why the worgen curse makes women grow taller than men, I have no idea, but there it is. It's also interesting that while the female is taller, every aspect of the male from the head and jaws to the hands and feet grows massively, while females see very little in the way of growth of those portions of their anatomy. The worgen male sports a massive maw of savage fangs, while the female's mouth (although still a large muzzle full of sharp teeth) is far less developed, almost fox-like. Much like the tauren or draenei, the worgen male is nearly double the width of the female.
Interesting that of our two new races, the goblins come off as nearly physically equivalent between genders, while worgen exaggerate the already striking dimorphism of their parent race -- especially considering that most Gilnean women you meet in the game are such astonishingly aggressive and forthright women.