While I'm no big fan of what King George the 2nd did while on his throne, creating the department of Homeland security wasn't such a bad idea. At the time, one of our greatest vulnerabilities from Islamic terrorism, or Chinese cyberwarfare as far as that goes, was that each of our various intelligence and police organizations were operating independantly, and not sharing information with each other, cuasing tragic inefficiencies--just think of that lost FBI report from the Minnestoa flight school which turned away one of the 9/11 hijackers wanting to just learn how to take off a jet, and not how to land it.
The Department of Homeland Security was designed to act like a big corpus callosum, integrating the thinking, and actions, of the diverse police and intelligence entities, with a director who was over the heads of each unit. While this hasn't eliminated interagency turf battles, it has reduced it a bit; and the DHS has improved the sharing of information within the intelligence agencies.
Unfortunately, it has also been quite obviously too tied to the political aspects of government, often acting in what appeared to be for political goals, and not for the security of our citizens. Just remember all of those conveniently timed orange alert levels near each federal elections.
So I say, let's keep the DHS, but revamp it to have greater political autonomy and efficiency.