Yeah... exactly like it should have went down. Although, I've yet to see whether the Mets picked up any of the ~$3.5 million remaining on Wagner's contract.
They got some value in return for Wagner, OF prospect Chris Carter (who Boston had no use for) and another player to be named later. They're probably worth giving up the two draft picks the Mets would have got after offering Wagner arbitration this winter and saving some cash.
The Red Sox make out great in this deal. Wagner almost vetoed the deal, as the Mets weren't going to let the Red Sox just claim him, and Wagner didn't want to go to any team that would pick up his option or offer him salary arbitration, unless he would end up as the closer. Obviously, that wouldn't happen with Jonathan Papelbon in Boston, but Wagner decided to go to Boston anyway. He'll get his option declined, but they most definitely will offer him arbitration, since some team will decide Wagner is worth the draft picks to come in and close on an incentive-laden deal.
This is a move the Cubs should have made. They have a gaping hole at the back of their bullpen, and acquiring Wagner would have helped. The option and arbitration wouldn't have been an issue since the Cubs could give him guarantees of the closer job, if he performs the rest of the way. The move also would have countered the Cardinals acquiring John Smoltz. The Cubs should have at least put in on a claim for him. I've yet to hear the reasoning why they didn't.
To me, not making a move or two over the last week signifies the team has given up on making the playoffs this year.