Actually if Larian doesn't ever intend to return to Illithid lore, I'd like some fleshing out of Mind Flayer material in-game through DLC. While we were promised Illithids, it feels they were merely a front for the game's real antagonists. I would have liked to see a Mind Flayer colony actively working against the Absolute beyond the handful of guys we meet. We meet one Mind Flayer in the Underdark, and that feels like a disservice. I'd have also liked to face different kinds of ceremorphosed creatures. Why no neothelid fight? Brainstealer dragon? MINDWITNESS?
Actually this would be pretty cool. Despite Larian marketing the game so much with mind flayer imagery (It's even in the logo!), this game surprisingly...doesn't go that much into mind flayer lore. It kind of gives the impression that mind flayers, when under the control of an elder brain, are drones. They're not really a hive mind in the sense we usually consider those, though; they're capable of individual, independent action, beliefs, and even personality.
I also feel like they might have missed on Githyanki lore a bit, or at least what I remember of it? It has been a while. But you kind of only see them as this super-strict military culture when they themselves are supposed to be decadent and highly individualistic. But I haven't done a Gith tav playthrough yet, maybe it shines through more there.
