The point of the video wasn't to hurt Hank, it was to create a mutually assured destruction situation with Hank.
I don't see Skylar as a monster, so much as a terrified, defeated woman.
Walt didn't kill Jesse out in the desert because he's stubborn, and he's emotional. He doesn't want to, and convinced himself he didn't need to. And he wouldn't have needed to if Jesse hadn't figured out he poisoned Brock.