I mean, it's an interesting discussion in some ways I suppose, but I really don't see whether the engine was originally planned to be fixable as all that relevant to the question of if the ending we have works well as an ending. My problem with the existing ending of Karlach's story was never "I'm mad that this character's good ending was cut." It's that her quest feels incomplete and the ending forced, because there's at least four different options I can think of that at least would have a decent chance of working that you're just not allowed to try, and the result is the only Origin character quest where you have no opportunity to have any useful impact on the outcome. If people liked it, great, I'm not going to tell you you have bad taste or whatever, but I just don't find the way her ending is handled right now satisfying at all.