From the articles i've read and interviews I've seen I honestly think he sees himself as a North man. There was just so much... shit... during his stint at Carlton. Clearly had problems with discipline, keeping himself healthy, relationships with the coaches. He was a whipping boy, and wouldn't have been considered a leader's arsehole.
Completely different story since coming here. I think reaching his peak (which he only managed here) and enjoying being the best he can be is what drives him these days. You see him get shitty with himself on field occasionally when he makes mistakes. He's become a team player too, he understands the value in that.
I suspect a fresh start where he was able to get rid of all that mental baggage from a decade of misery at Carlton, and a fresh set of eyes on his injury plagued body, were enough for his attitude to completely change. And then when he started dominating and actually getting respect? Being cheered by the crowd and celebrated, instead of having snide comments made about him constantly? Looks and acts like a completely different man.