While I share your optimism about the team as a whole, I don't think the defense is all that great at the moment.
I'm sure that we are all happy to know that X has spent time in Arizona attempting to become more quick a foot and all. I just don't know that he will be so much better than what he was last year at short. His range and footwork / throws to first still concern me. I'm from Missouri when it comes to his ability to be better than average at his position. He has to show me.
Sandoval, despite being a hunk of goo, should play decent 3rd base unless he becomes injured. Pedroia will be himself, I assume. Napoili says he is a little behind schedule in his preparation because of the ghastly surgery to his face. I expect that once he catches up, he will once again be at a near Gold Glove level at first.
Overall, I don't believe the infield defense is so much improved. This is worrisome given the Sox professed commitment to ground ball starting pitching.
Now the outfield is a real question mark if not still a total mess. Bradley will not be in Center. Betts is still a novice in the outfield. Castilllo is unproven at best. Hanley is a potential disaster in Left. I'm just hoping that he can play about as well as Gomes. Victorino could return to play Gold Glove D in right field.
Catching appears to be a real strength defensively.
Overall, I can not say with a straight face that the Sox Defense is all that great.