Not to butt in, but I saw a post recently explaining that editing would be disallowed after a post had either been up for a certain period or else had been responded to due to too much abuse of the editing function. I think that what it referred to was people going back cleaning up or correcting posts to cover their misbehavior or mistakes, such as I have seen happen in the event of contentious debate.
Whatever the reasons, personally I find the new feature to be a major pain in the butt. I often post articles I write here in CZ before they appear anywhere else other than my own website. Though I try to post articles that are close to final form, I do find typos and other oops and I also find added material or better ways to word the articles. Another example is where I respond to people seeking help and later find some added information that could be useful. And then there are also the typos and such in other posts that I catch later on. If all I did was post on CZ instead of the many, many other things I am constantly doing, perhaps I would catch such items faster. But such is not the case and I find it more than a little annoying.
Somewhat comically, the edit disallowed function has been applied to my posts in my private forum too. I say comically because as the owner/moderator I can edit the posts regardless.
If only there were a way to apply that to selected people who have a history of abusing the feature??????