I actually think this would be a step at least in the right direction and an easy fix for them to implement. That they haven't done this (which i guess we will find out in ShB) to me is more suspect. That said, it would possibly make the disappointment more palpable and would also rob them of any hype generation should they wish to add them later. I think the way Yoshi p has responded implies that it is likely we will get them at some point. The Dev team routinely go out of their way to provide what the fans want, i cant see this being any different. One solution would be maybe to have all gear under level 50 just display as the racial armour to start with. Which would cut the amount of work they need to do quite considerably.
But then i don't think its the issue of updating all that gear, that's part of it, but it seems its more the issue around keeping the patch cycles on a 3.5 month release schedule. Arguably, this is going to become more of a problem in 6.0 with further jobs. Could be that Yoshi P is simply waiting to see how ShB does before committing vast resources to their development. Which to me makes sense. If ShB cans then they wont have the resource, but if it does well (and fantasia sales on mogstation rocket) gives more justification to allocating that resource.
The problem with his answer is that it is limited in the scope of why they choose the current genders, it is not a response to why they won't add the missing ones. That, i think makes all the difference and gives me confidence we may see them someday.
Afterall, look at their response to the headgear - if that doesn't show their dedication, nothing will.
Then again, I could be completely wrong, its speculation either way.