Oh, not arguing against that ending, totally agree that it's a poingnant one should the right context be built through the proper gameplay choices! What's there is fine, what's not fine is what should be there, but isn't!
My point was that what information there is in the game does not support the railroading into
die, die but with tentacles, or three flavours of go to Hell.
. Every single detail points toward there being a fourth, happy ending for her, but it leads nowhere.
Which, as Nary A Care has so elloquently pointed out, is made all the worse through the fact that when playing as Karlach, she totally has a happy ending. Which is achieved through exactly the elements which go nowhere when having her as second fiddle.