I like that take. The first season, the pilot in particular, illustrates that Walt begins with his family as the primary motivation.
But the official turning point, to me, is when he blows up Tuco's office. Looking back, you can trace Walt's addiction to power and influence back to when he's celebrating in the Aztec with his hat on.
Getting into the philosophy of the show, I think Gilligan's point might be that the concept of inherent badness is just a comforting lie that we tell ourselves. Every person is capable of "breaking bad". How many characters on the show haven't resorted to their dark side under pressure? Pretty much just Hank and Walt Jr. And even Hank mistreated Marie emotionally when he was paralyzed.
The worst thing that Skyler could have done was to verbalize that she fears Walt. Up until now, she had the upper hand because she could dangle their relationship like a carrot.