In StackOverflow, editing a question or answer seemed a useful ability as a broken answer could sometimes become a great one with a little tweak or two. As a public service, editing seems a positive tool (with some potential pitfalls).
Here, the possibilities for evil seem much greater than the possibilities for good. A grammar or spelling fix might be welcomed. Removing argumentative or prejudiced words, if done with care and commented upon, might fly. Adding a link or two probably wouldn't hurt. But many other forms of editing could be taken as underhanded or assaults on an author's authority.
What pitfalls do you see for editors of a site for Philosophy?