Seems like a lot of people think he's going to opt out to escape the psychological harm done to him in NY. I don't see how that's relevant anymore though, because he's obviously gotten over whatever mental block he's had in previous years, and the booing has completely vanished.
Sure, the NY media is still hassling him, but a player of his caliber should expect that from all news media outlets. It won't change dramatically going from, say, NY to LAA, because the expectations of a 40 HR, 300+ AVG season will still be there for the best baseball player in the league.
I'm sure he realizes this, and he also must know that if anything, he'll be bashed from the media even more for opting out because for one, he'll be viewed as greedy and going after the money, and two, he couldn't handle the NY pressure.
Even if he hadn't had such a spectacular season this year I would have believed that he would not opt out, and now, with the great season, I am absolutely certain that he is staying.
And as for the Yankee legacy comments, you can't argue that there isn't something special about being a Yankee for the simple reason that a lot of actual baseball players have claimed it as one of their reasons for joining New York. Whether you believe there is some mystique or aura about being a Yankee or don't believe in it, the people who play the game do, and that's all that matters.