The problem has become so severe that nothing short of an Edward Snowden-style leak may be needed to increase transparency at the DHS.
Such a leak is just as likely to have exactly the opposite effect. The Snowden leak hasn't exactly made the NSA any more forthcoming regarding their activities. No, the ONLY thing that is going to force DHS to be more transparent in the long run is a motivated Congress. Oversight of the executive branch is after all their job. But since the Dems and Reps are so busy trying to grab power they can't be bothered. The judiciary is no help since they have their head stuck in the sand over standing that they are worse than useless. So the executive branch can do whatever the hell they like without consequence until at least one of the other branches of government starts doing their damn job. All a leak is likely to do is show them what they need to do the be even less transparent than they already are.