John,
I agree with most of what you said except the last one (about Mantei). I don't know if he'll be a "surprise" really, since the Sox know what he's capable of. I think he'll be decent, (ERA in the 3's) but not overpowering. Just my opinion.
You're right about Brown and Johnson. Both are good pitchers (with bad attitudes, but that shouldn't change how they pitch), and both should be reliable starters for New York next year. I predict them both in the low 3's in ERA. They should have 30 wins between them by the end of the season.
Pavano isn't bad, but he can't be expected to pitch as well as he did in Florida. I say 15ish wins with an ERA around 4.
Bernie Williams is no longer in his prime, but he's not exactly Timo Perez out there either. He's still good for 20 homers and a .270ish batting average. His contract is up after 2005, and considering the Braves are always cutting salary, I wouldn't be surprised to see Andruw Jones as the starting CF in 2006. That being said, like others have noted, the Yankees may opt for a Juan Pierre-type centerfielder who can leadoff.
I'm not sure about Giambi though. I wouldn't be surprised if the Yankees still try to get out of his contract, and if they do, they'll probably give more playing time to Tino. And who knows how Giambi will hit when he isn't taking steroids? How long has he been using them? I say the Yankees can expect .270 with at least 20 HR from their first base position in 05.
All in all, the Yankees have questions, but so do ALL teams in January. Anyone who expects the Yankees to fall out of contention will be dissapointed in 2005.
I think the Yankees biggest weakness right now is depth. If one of their starters goes down, they don't have reliable backups. Who plays RF if Sheffield goes on the DL? Bubba Crosby? eek. Who's their 5th starter if Brown, Johnson, or Mussina get hurt?
Will they be unbeatable? No. Will they be in contention? Yes.