I will never, ever be able to accept that it is ok for the police to shoot a person who they do not see carrying a weapon. There is no circumstance in which you can say you feared for your life if you did not see a weapon. And if you legitimately did fear for your life when you didn't see a weapon then maybe you shouldn't be a police officer.
It doesn't take a weapon to kill someone. A rather infamous example in recent years is the death of Eric Gardner. Deadly force is deadly force—regardless of the form it comes in.