I don't know if there's a proper amount of contrition to be shown after accidentally killing somebody. What I know for sure is that doing everything you can to blame anybody but yourself makes you an asshole.
To this day, Alec Baldwin has taken no responsibility upon himself. For anyone who knows how guns work, he was lying from the moment that he spoke publicly. As more evidence arose, the extent of his lies became all the more apparent and egregious.
What's done is done and we'll never get Halyna Hutchins back. What can be done and what should be done is Baldwin telling the truth about what happened, pointing a finger at himself, and saying "I'm sorry." until he's out of breath.