Not trading Roy Halladay watch

Haven't had much time to blog this week, or today, but I thought this recent turn in the Halladay trade epic is weird. Apparently the hold up is between whether to include Carrasco or Drabek with Happ. This honestly makes no sense to me. As good as Roy is how do they figure to get so much better substituting him for Happ instead of adding Roy to what they already have? If your goal is to do as much damage as possible with Roy over the next season and a half, why not collect the best players NOW around him.