I thought we were talking about awkwardly applying real life biology.
Look, you and I both know the reason that sexual dimorphism is a thing in WoW (and that it goes the way it does) is because the designers made a choice that the females would be smaller, skinnier, and have big eyes and lips so that no one got confused and ran off a cliff in panic because they couldn’t figure out if the cow monster was a boy or a girl. I’m just saying applying real life biology is pretty dodgy to a fantasy universe where most races haven’t even been around for a million years (and are also robots).
Though it is entirely possible that female draenei are smaller, faster, and stronger so that their ancestors could fight other lead females over territory with their horns while the males gathered food and plodded around (hence them being bigger and lacking the main draenei display/defensive trait of HORNS). Only the strongest and best headbutters maintained territory and passed on their traits to their progeny – only the ancestoral female draenei with the sharpest, most effective horns. It was a short and brutal life on the primitive savannah of Argus. Modern draenei, of course, are past such things and even let males participate in government. Though nothing spells security to the subconscious draenei mind like a leader with really big horns.
…Or not, because frankly, that’s ridiculous. But so is extrapolating that the reason that WoW races look the way they do is sexual selection on males to be BIG AND STRONK JUST LIKE HUMANS (which are actually fairly low on dimorphism for great apes so there’s that).