Yasuke is actually a fantastic choice as far as history/narrative goes.
A shame the game looks like more generic Assassin's Creed Mapfucking+Crowd Supermurder.
Which is fine if that's your thing, but I haven't been thrilled by an AC game since... well, AC1.
Japanese women aren't treated the same as men today, let alone in that time period which is the 15th century ...
Yeah, true.
What does that have to do with what was being discussed? They asked for a playable option of someone of the "appropriate ethnicity" to represent the culture (and I'm not even qualified to explain that kettle of worms). There is one, she's also a woman.
They didn't ask for a "playable, ethnically-and-culturally Japanese character that is primed to interact with and take advantage of the stupendously patriarchal system of AC Shadow's era of Japan, i.e. a Japanese man". Possibly because they realized how bonkers it would be to request that. And a patriarchally-advantaged playable character has hardly core to the identity of AC, to be making a stink now.