If history has shown us anything, the fears of extreme government overreach and oppression of peoples is not a relic of the past.
While related, this is not the concern that Justice Stevens considers "a relic." It is the narrower "[c]oncern that a national standing army might pose a threat to the security of the separate states" that "led to the adoption of that amendment." Furthermore, I don't see how "fears of extreme government overreach and oppression," as you put it, necessitate the civilian possession of firearms. I might be a liberal, wishful-thinking rube, but that's my opinion considering the state of the military technology that the United States armed forces could bring to bear in the hypothetical scenario where our national standing army decides to neutralize the states.
I think the Court in 2008 constitutionalized the common law right to self-defense. It then simultaneously augmented this newfound national right with a firearm. Scalia, who wrote the opinion in Heller, was a critic of the Court's historic strategy to incorporate the Bill of Rights through the Due Process Clause of the Fourteenth Amendment. Yet he adopted that strategy when he saw fit (though "reservedly," he was keen to qualify).
I agree with Stevens. Repeal the 2A. It'll likely never happen. I've written before--Hubski comment and short article--on the near-impossibility that amending the constitution is. See how difficult simple legislation has been to pass, let alone the two supermajorities. It seems fantasy that an amendment would get through. That said, a proposal to amend the Constitution to ban flag-desecration came one vote short in the Senate in 2006.