His compound sounds like one hell of a place. Though it does seem surprising that suspicions hadn't been raised by anyone earlier, since it's a huge complex in a colonial suburb not far from Islamabad (which happens to be where the Pakistani military's largest base is situated).
Of course, it won't make any positive impact in the fight against terrorism, but it's a symbolic strike. It's also interesting that the Pakistani government was told nothing of the operation in advance, but given its gravity and the necessary security that's understandable.