If the MC turns out to be offspring of a Bhaalspawn, and the Illithid were only capturing "specials" it could go some way to explaining why your MC is taken. You as the MC don't know you are the offspring of a Bhaalspawn so even if you have all your memories you still don't know. They don't need to give you any abilities or powers just being that would be enough to make you special.
To make this a thing what you'd need is some indication on the crashed ship that the Illithid were collecting "specials". You ask yourself why am I special and what's so special about all these other folks I keep meeting? This would make the discovery of their differences acceptable.
This would also tie the game back to BG1 and 2.
Right now it does seem like all the companions are a freak show. You could be part of the freak show.
