I'm a bit lost where you're going with the celebrity examples, but for the first bit of your post - I don't think the two other examples have used the same face at all - or if it's the same basic face, the eyes are quite different and they don't look the same to me.
Anyway, if a face can look African when paired with African colouration, and Caucasian when paired with Caucasian colouration, I feel like that's not quite the same as "not being able to make an African-looking character at all", even if you're more restricted in the choices.
And again, you're further restricted if you're set on being able to create the appearance you want specifically with a Midlander Hyuran when ultimately the character creator is quite limited for each single race but does add up to having more variety spread across the different races. Midlanders cater to a particular subset of human appearances, Highlanders to a different subset (and further appearance options are available from the other not-perfectly-human races). I don't know if they've covered all the bases between them but I think it's better that they have their own niches with subtler variations than to try and make one race cover everything.
Hyurans are also the one race where they've actually split the clans to have completely different appearances - effectively doubling the available number of 'human' face options versus any of the other races (even if it it firmly divided into two sets of options). For any other race, the models for the clans are identical and it just comes down to differences in colouration or details in the eyes.
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On the issue of whether Hyurans=humans and whether they need to have all real-world races covered, there are two ways to look at it.
On the one hand, Hyurans (Midlander and Highlander together) are the one race that are physically human - height somewhere in the 150-190cm range, small rounded ears, skin tone varying from peach to brown.
But there's another element that defines Earth-humans: we're the one sapient race found across the planet. This is not the case in Hydaelyn, where there are many other races who have physical features we consider 'non-human' but are still culturally equivalent to them.
All Hyuran cultures = real world human cultures, but not all human cultures = Hyuran. Some translate to being Miqo'te desert tribes or Xaela or beastmen.
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And again, there's the question of geography. Hydaelyn is clearly Earth-inspired, and we have Eorzea (= Europe and the Near East), Ilsabard (Russia and middle Asia?), Othard (east Asia) and the vaguely referenced 'New World' (apparently the Americas, judging by that one glamour set) and the mysterious southern continent of Meracydia, origin of the Warring Triad.
Meracydia is the one place we know nothing about - by deduction, it may equate to either Africa or Australia, both candidates for local Hyurans being dark-skinned but only if they exist in the first place. The lorebook doesn't say what kind of people live there - only that much of it was rendered uninhabitable by the ancient war with Allag, and the few modern inhabitants are hostile to outsiders, thus the lack of Eorzean knowledge about the place. (The only possible indication that there were Hyurans there, at least in the past, is that there's one among Sophia's 'demiurges' - but they are transformed in appearance and can't be seen as any particular race, or it could have been a captured Allagan woman rather than a native Meracydian anyway.) The only Meracydian races specifically mentioned in the lorebook are the 'tree-beings' and 'centaurs' that summoned Sephirot and Zurvan, respectively, and also dragons if they are as sapient as their Eorzean cousins.
So anyway, I may have gone a bit off-track, but my point is - the world of Hydaelyn has no definite Africa equivalent for "African" Hyurans to originate from, so from a lore-building perspective, where would an African-looking Hyuran have come from? The argument that "it's medieval Europe and there actually were Africans in medieval Europe" doesn't simply transfer over, because those Africans still had to migrate there, which they can't if there's no Africa to migrate from.
You can get creative with the lore and say they're Meracydian... for now. But if we ever go there as part of the story and it turns out that actual Meracydians aren't like that, it's back to the question of "how can Africans exist if there's no Africa?"
Perhaps you don't care about lore yourself, but it's still something to think about.
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On the "lack of fuller lips", maybe they don't go quite as large as you want but there *is* a noticable difference between the the mouth options. Is the 'full lips' option (always option #2 if I remember correctly) not big enough?
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For what it's worth, I wouldn't count Highlanders as 'black' (ie. by my understanding, either African or Aboriginal Australian, depending on context - and I assume everyone else here is meaning African. (Though still unclear about correctness of actually using the term in either case, and would avoid it myself.))
Geographically, I thought Ala Mhigo is roughly equivalent to the Middle East? I don't know enough of the cultures around that part of the world to be able to identify anything more specific. Please do let me know if there's an actual location they are based on.
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Ultimately, unless they completely overhaul the character creator, I don't think there's any way they can add more 'face elements' into it without removing the current ones, and I doubt they would do that. Maybe they could have done better at the start, but it wasn't - and it couldn't be changed now without affecting some people's existing characters.
On the other hand, new hairstyles are added constantly. Ask for those.