Probably a combination of change of scenery, a fresh set of coaching eyes on him, and the competition from Swayman, caused him to re-evaluate his game. I don't think that reflects one way or the other on the coaching he got in Buffalo. If he'd been in Boston the whole time, would he have also developed the goaltending habits he did with the Sabres? Would there been another hole in his game that leaving Boston would fix?
Interesting conversation, but that's about all it is to me.
And how could you listen to the Bahston broadcast without your ears bleeding?