Following a quick read and subsequent CTRL + f search, I see nowhere in this article where Justice Stevens attempts to clearly define the crucial term "militia," even when referencing it as being part of a state's apparatus. Does he mean the states' National Guard forces? If so, then the door is opened for confiscation of every private citizen's firearms with a special focus on those too old to serve in the Guard. Does he mean any private organization claiming to be a militia? If so, the controversial militia elements in every single state in the Union will be given additional legitimacy and a huge surge in membership. Does he mean something else? Without looking at his decision history I have no idea what Justice Stevens means when he uses the term "militia," since it could conceivably mean anything from a few guys that meet up every few months for a range trip to an actual government organization (Nat'l Guard.)
I don't think these five words solve anything, let alone "fix" the Second Amendment. And there's a reason the Founders delegated Constitution-interpreting power to the Judiciary branch, and not the Legislative. But this kind of dialogue is healthy, so I'm glad I read the article.