Pete wants to be more to Sterling Cooper (to everyone, really) than his family name. You're right, he's been portrayed as more forward-thinking than one might expect from his character right off the bat. But he's ready for a change from the 'old guard'. Scenes with his father when he asked for money, the telling of his family story when he and Trudy were just buying their apartment...he wants to cast it off, badly.

The shot of him in the black turtleneck was interesting...