I've been saying so for years, but two law professors point out in the New York Times that the overwhelming majority of thousands of habeas claims are denied, and suggests that the writ be limited to capital cases and claims of actual innocence.
Given the availability of direct review and collateral attack of convictions in state courts (and the possibility U.S. Supreme Court review of the federal constitutional implications of thosedecisions), I would agree that we generally don't need a third level of review in the federal courts. I would go further than Hoffman and King and restrict the writ to cases of actual innocence; while federal courts are more likely to grant habeas petitions in the capital context, it generally appears that they do so for purposes of protesting capital punishment rather than because capital cases are handled more constitutionally sloppily than run-of-the-mill felonies. If anything, the blizzard of habeas cases in the federal courts hurts the innocent, because it's harder for their habeas petitions to stand out amongst the mass of frivolous cases. Money currently devoted to litigating these thousands of petitions would be better served upgrading the public-defender system.