Fujino already made it clear he wouldn't add Yui, she's in the same level of "exists but for some reason isn't around" that Silica, but even 'worse' because Fujino CAN'T add Yui to the game because if she had been around even once since the beginning then Inoda would have never been able to do anything to Asuna, nor would Asuna have found herself in any of the situations she did in-game because Yui would have prevented them all XD Is another plot-hole that the NTR world has to make you forcibly ignore, like the incongruency of the Fairy Dance Arc having happened yet NOT because Kirito apparently never met Leafa/Suguha in-game just so her confession couldn't have happened and her "not-NTR" plot could be justified XP
Also, man, everyone suddenly going into serious analysis of the characters and the seriousness/depth of the plot in the past 24 hours is kinda hilarious...people, the truth is, there is NOTHING at all even remotely accurate or realistic in Fujino's game about literally ANY of the SAO characters in the slightest, nor could it be justified at all, because if this was actually a faithful portrayal of SAO then nobody would ever be NTR-ed, Canon Asuna could never be "corrupted" nor would Kirito or his friends allow it because they're not the moronic twisted mockeries that this game has of them just so the "Almost Everything in this World Runs in NTR Logic" can work
At the end of the day, any kinda enjoyment you can have of the 'NTR' aspect of this game has to come after acknowledging it's completely dumb and unrealistic for the characters to be involved in (Like how someone mentioned Suguha was drugged/blackmailed/raped, the irony is that this plot never would have actually worked if it happened in a world NOT running in NTR logic because Suguha would have never accepted going out with Hebishima in the first place no matter how much he begged, her completely and brutally rejecting a guy continuously without giving him the slightest chance is literally part of her Canon character arc, and she actually was kinda friends with that loser XD!).
It may be easier for me to say that as someone that actually genuinely likes SAO and its characters, and doesn't really care for NTR but it's here because the Hentai is good and Fujino's work is honestly amazing, but the best thing to do is just enjoy what you like or not about the game, really, and praise Fujino-sama for his hard work