Ultimately, the thing about the warfare is that because the Xaela live on a steppe with more scarce resources, they can't afford to expend as much energy. So the smaller size of the women is an advantage in a certain way; even if it makes them physically weaker, there can be more female fighters out there because they just don't require the upkeep a male soldier does. Besides, you're conflating muscle size with strength again; the two are connected but not entirely dependent on one another. While the women are lithe, there's nothing stating they're incapable warriors who regularly lose battles to men due to their smaller stature.
I don't claim to know why they made the Xaela the "original" Au Ra social system and the Raen the "modified" version but developed their designs dependent on the more urbanized clan. My best guess would be that by making big and tough males who appeal to Western ideals of masculinity and prim and proper females who appeal to Eastern ideals of femininity, they hoped to minimize complaints and satisfy a greater group of people than if they went with just one of those two groups alone. At the end of the day everyone cannot be pleased no matter how hard they work or what they do, and the Devs (supposedly) ran themselves ragged getting this expansion done. I'm willing to overlook the lack of a "tough" option for Au Ra women in lieu of this for a number of reasons.
The thing is, the bigger they make the model the easier it is to notice the pixels and imperfections in it unless it's designed to be that big. So if they made the Au Ra women have a great height range, anything outside of a certain range would granulate clothing and armor. Yes, it can be done, but the results might not necessarily be pretty.
No, none of the clans present in the game are "special snowflake" material. While they might be kind of quirky, they don't break the rules of the world in that regard. The "eugenics for taller people" clan is the only one that might fall under this; everything else, from using cloud- and wavekin clicks in their speech, to having their skin tone adapt to the environment, to being able to hold their breath for long periods of time, and even the frequent twin birthrate clan isn't too farfetched and doesn't modify their biology to suit. Declaring "my Au Ra is from a special, undiscovered clan where the women are as tall as the men" breaks what's already been established about their biology (and even what's possible in-game) to make them what you want instead of accepting what they are.
I don't know why you would think the Roegadyn show greater sexual dimorphism than the Au Ra. The only real difference between Roegadyn sexes is the muscle mass (and even then, female Roegadyn are comparatively more muscular than the females of other races, excepting perhaps Highlander Hyur). Women are about as tall as the men, maybe a little shorter for realism. And while they're not the most-played race, I've run into enough Roegadyn PCs to say they're by no means unpopular. Elezen, on the other hand, I don't know if anyone really likes them because they're kind of noodly (in my opinion).
There is plenty of doubt that the next female PC race will be "cute girls." Until they show a design we don't know what they have in mind, or if they even have anything in mind at all. Declaring that Au Ra women point to an endless steam of cute / moƩ / nadeshiko designs for the females of new races is jumping the gun waaaaaaaaay early. If they implement another race and if the women are cute waifs again without a similar structure for the men, I'll pick up that phone.
I just finished the DRK pre-Heavensward storyline, and it's impossible to say who or what Fray really is without spoiling pretty much everything. Suffice to say, though, I'm quite glad I did the DRK storyline prior to properly touching Heavensward; it makes sense, in a certain way.
An' don't worry about it. I appreciate the offer, but like the blue hair with white highlights of my original Highlander avatar it's grown on me. :P
