You can't evaluate a trade until down the line unless the player acquired goes on to win a championship right when you get him.
So if Edwin Jackson went on to win a championship with the Sox last year, you could automatically call it a good trade, and whatever Hudson did in his career would still make the trade worth it. Or even if they win this year with Jackson in the rotation, fine, good trade.
However, without actually making the playoffs, the trade hasn't been worth it so far.
And as far as Hudson beating the Padres or Twins or whomever, who cares? They're major league teams, and he beat them. Mark Buehrle has made a career on beating bad teams. Nothing against Buehrle, but he's just doing what he's supposed to.