I agree with authors having the last word, and some edits in freely-editable content sites do decrease the value of the content.
editing - author has last word
I very much appreciate when someone fixes my typos or grammar, or makes my language clearer, or adds an image, figure, example. Unfortunately, more often than not, people who edit my stackoverflow messages make them less precise, more confusing, and insert errors (which people then assume came from me). So while I love the idea of improving and perfecting articles, I don't know the best way to achieve this in practice in a wide-open community setting such as this. My opinion is, the original author must have final say on his article. My favored solution is for edits to be sent to the author, who can then choose to incorporate them or not. A tool that emphasizes changes with different color text would make this process easy for authors and editors.
My problem is with authors that go MIA, and then any suggested edits never get reviewed.
I'm not proposing that anyone in the community can edit it (it's not a wiki), but rather that other authors, moderators, or high-standing community members can edit it. Sure, the author should be able to approve edits (and tweak the edits before applying them) before they are visible, but if 30 days go buy and the author neither rejects or approves the edit, it should be auto-approved (again, these edits are from other authors and moderators).
Article edits should have the whole history just like individual forum posts already do, so the author can later rollback the edit if needed.
I'm not really bothered by the whole, "Oh no! The article used it's instead of its!" type of edits (though extremely bad spelling errors can be distracting), I'm more worried about situations where the article means one thing, but accidentally says another.
A recent example of this that I came across someplace else, was an article that said, in passing, that a 64 bit int holds twice as high a number as a 32 bit integer, which is wrong - it holds way more than double. The article also had some other errors that included good advice that was poorly phrased in such a way that beginners would get the wrong idea and adopt bad practices. It's those kinds of errors that can be easily caught by a community, and suggested as edits, but that need to be corrected even if a author accidentally changed his email address over the years.
People reviewing articles should even be able to suggest edits while reviewing the article, since they're actually looking for mistakes while reviewing it.