The problem with the idea that Walt's descent into crime revealed he's always been a monster is that like - on the one hand, it's true that it revealed a darkness in him that was probably already there, but on the other hand, if he hadn't have gotten cancer and gone on that ride-along with Hank, he wouldn't have gotten into crime and therefore wouldn't have killed all those people and terrorized his family.
There's nothing to suggest he was a "bad" person before all this. His family clearly loved him a lot and there is no evidence he ever mistreated them, and he seemed to be a pretty good teacher who enjoyed his job. Sure, he was prideful and had a chip on his shoulder, but those aren't "evil" traits. He was just some guy.
He became evil through the choices he made, not because he was born that way
(via @septembersghost )
YES, this is what I was getting at. I think people who hate Walt from minute one because they already know he's a villain missed out on a really powerful effect a spoiler-free view gives you, because Walt IS sympathetic in the beginning, and he really struggles with the evil he's doing.
But instead of getting better after hitting rock bottom, Walt continues tunneling straight to hell. It's so shocking to see someone you cared about do all these evil things. It's exactly the same feeling Skyler and Jesse have. You get to go on the same journey, and you can understand why Skyler and Jesse struggle so much instead of going to the cops or selling him out.
It's because they love him.
This really pairs with BCS's whole thesis about love not being enough. Skyler and Jesse loved Walt, but it didn't change him or stop him from hurting them. Walt loved them too (and I think it's really missing the point to claim that Walt felt nothing for his family and Jesse) - just not enough to stop himself.