First off, thanks for bringing this up here. This is exactly how these older, controversial* questions should be handled. Discussion was mostly civil, focused on the merits of the various answers, and voting on SO itself served to illustrate the lack of clear consensus - the perfect recipe for a historical lock...
*I don't actually recall this being a particularly controversial in the past, but it has obviously stirred up some controversy recently.
For the past few weeks, I've been toying with various ideas for how we can help formalize the process for using the "historical significance" close reason. This lock reason is currently our test-bed for developing a strategy for archiving questions and their answers that should be preserved in some fashion, even if no longer needed or wanted as living Q&A on the site itself. Robert Cartaino had the idea of effectively eulogizing these - writing a short introduction that explains to future readers,
- Why they were asked and answered to begin with
- What gives them lasting value
I like this idea. If something is worth keeping, it should be possible to explain why - that's my primary motivation for asking that these posts be brought up for consideration here on Meta.
You and Adam come close to what I'm looking for. I would justify the importance of the question as follows:
On a personal note, I was never particularly proud of my answer there, and certainly never expected it to last this long... I resisted the urge to delete it for three years because it provided me with a frequent reminder not to get too self-righteous when moderating other people's work.