On my very first playthrough of DoS2 I ended up killing Sebille and leaving her behind. I didn't get to learn her story and my opinion of her character pretty much mirrored how most people seem to view Astarion. It was only on subsequent playthroughs that I took her with and learned the rest of it.
And. My opinion of her didn't really change that much, but it did change some, I'll admit. Maybe I just found other characters more sympathetic. It's interesting how people judge the whole character based on the first act of the game, Sebille and Astarion both, and how people seem eager to take Astarion, a known liar, at his word. I don't expect a full heel turn in his future, but I do expect a version of Sebille's kill the slave master storyline, just with the names and actors swapped out.
But the community reaction to both Sebille and Astarion is absolutely the same, at least judging by conversations based on this forum and reddit. They are both the most killed and the most disliked of the companions so far. The only difference seems to be that occasionally Astarion is funny, which means people kill him slightly less.
