I just finished the game, having abstained from using any Illithid powers the whole game, and romanced Lae'zel too so of course I wasn't about to let the Emperor "absorb" Orpheus... All I can say is that for the breadth of options we have throughout the entire game, I'm incredulous that it came down to either become an Illithid (and have Lae'zel be grateful, yet disgusted), or condemn the Githyanki to Vlaakith seemingly forever (Karlach was not in my party).
It makes 0 sense that the Emperor would turn against the very enemy it's been fighting against the whole game, especially since if the player turns into a mind flayer they can cooperate with Orpheus rather than needing to "absorb" him.
Honestly, I felt sick to my stomach seeing my wholesome, loving paladin destroyed like this, without even the dignity of being able to continue wearing her own armor... All game long, we're shown that every time we think there's a binary choice that it's a false dichotomy and that there's always another way, so it really feels like a slap in the face to have it end up like this.
Not sure I even see the point in trying another playthru at this point. 220+ hours, and instead of joy and a sense of accomplishment, it's sorrow and a sense of loss.
My Tav deserved better, WE deserve better.
This to me is why the people talking about how Evil does not have a playthrough, makes no sense. Good has nothing but bad choices and little in the way of a "good" reward. Even forgetting the romances for a minute, you are left with becoming something you have been fighting against the entire campaign, making someone else become this abomination or trusting an Illithid to be "good".