Dr. Drang also dislikes window shadows in screenshots:
The problem arose because I was including the drop shadow in window screenshots. There are some, like Dan Benjamin, who think this is an abomination. I agree that the shadows are too big, but don’t like the “open” edges of window screenshots that don’t have the shadow.
Drang’s solution solves the main problems some people have with both sides of the com.apple.screencapture disable-shadow -bool coin. I may poke around in this a bit.
Update: Here’s a link to a more updated post by the good doctor on the subject.