I played world of warcraft for many years, and actually, one of my guild mates' husbands had been a designer for the original game, though he did things like giraffes and bunnies rather than night elves in chain mail

From what I knew, he was a normal guy, though he worked a lot of hours.
One thing I do remember was the discussion that would ensue whenever a new "armor tier" design came out. People of different classes would gloat or bemoan what the designers had inflicted on their characters this time around. Sometimes it was amazing how ugly something was (and yes, there was some eye rolling when they started to add bare spots and plunging necklines to the female armor sets and ever-larger pauldrons to the male).
Clearly, they got it wrong sometimes, which was sort of surprising, what with all the alpha and beta testing they did with these things before they came out. I always suspected the people they got feedback from were not always "normal" players. So you're right: it is not fair to characterize the design crews themselves as nerdy (I'm sure they were often annoyed when sensible ideas were vetoed or modified), but the people who provided the feedback about what was "attractive" and "appealing" to the average player might have been.
Still, no one I knew ever quit playing WoW because they hated a particular set of armor, and got pulled in initially because a real life friend started playing. Sure other games are the same, once they hook you in. Still, if I'm buying a game I haven't heard of, and the cover art makes it look like the female characters are all going to be half-clad, I might be less interested in it.