Another problem with those reveals (and other things like the "romance") is that they happen too fast. No idea if that is because Larian wanted to cram it into the EA, but after a few hours you don't have a connection to the characters (and the way most characters behave certainly does not help) and thus you do not care about the big reveal. And that is in addition to you never really have a reason to believe that they are anything else because its so obvious.
Compare that to Wrath of the Righteous
Camillas reveal at the end, if you follow her quest line.
You could already suspect it, but most people still had doubts about her at least. Also, it wasn't obvious from the start who she is with a cringe name like Shadowheart wearing Shar symbols. You had hints, but that is all.