I remember in a stream, they said the right choices in DAO n 2, will have bad consequences. And bad choices, will have a good outcome. And Anders says he'll meet an horrible end, doing something great. I seriously doubt the knife to the back was, THAT, horrible. It sounded more like he'd sacrifice himself. He could of sacrificed himself to protect the Inquisitor. But you killed him, meaning no Anders to sacrifice himself to protect the Inquisitor, and you die.
I like this, why? because my hawke and my quizzy are two different people.
Felica hawke, a lovable yet sarcastic rogue, was friends with nearly everone and fell in love with choirboy sebastian. She was protective of her family, she sided with the mages to save bethany and no more. She did not agree with anders, and she rather became fed up and hated him near the end. So she knifed him.
If this creates negative outcomes for her and my quizzy, well guess what? people have to deal with the consquenses of their actions. I am totaly expecting the OGB to issues and I like that. 