Being happy the team you were traded to has some close friends on it, and telling Buffalo fans you're excited to play for them, doesn't necessarily mean you wanted to be traded off a team that's a Cup favorite.
Neither does talking with your friend about the possibility of playing together one day. I'd bet Nate had those same type of conversations with Sid early in his career. Sakic probably talked with friends back in Vancouver about playing for the Nucks early in his career too.
And I just disagree strongly both with the idea he had to play a top pair role, and that he never would have had one in Colorado. Very possible Toews could have taken a step back and allowed Bo to play with Cale more often, and Toews to play a lesser role as he gets into his 30's..
He's not a guarantee to play a bigger role in Buffalo either. In fact, given Dahlin's struggles, I think they may toy with the idea of moving Dahlin back to the left side, and pairing him with a righty like Jokiharju, and playing Bo on the second pair. So it might not be that different than in Colorado.