I remember ridiculing Stewart's opinion when I was in law school.
I've since realized that his approach was closer to appropriate than the other justices. Unlike Brennan, White, et al, he recognized that the line between "obscene" and "non-obscene" was inherently vague. He didn't have the other justice's hubris. He didn't believe that it was possible to draw fine lines between limp dicks and erections.
And, I believe, he also recognized that line drawing on vague concepts helps no one except the lawyers and others who recognize that vagueness+line-drawing provides an opportunity to manipulate the rules to their benefit ("everyone does it").
That's why the legalistic approach is so limited. If you try to get a rule that fits everything, including the vague bits, if you try to get perfect justice, all you do is reduce justice to a case of who can afford the best lawyers.
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)