For how long can users edit their thread? Days? Weeks?
Can this limit be raised or lowered based on number of posts / length of membership?
Can the server side do a 'diff' on each edit, and reject the edit if there are too many deletions? It will surely put some of them off if they can only delete their posts if they have to do it 3 lines at a time.
Can this limit be raised or lowered based on number of posts / length of membership?
Probably, but there's no point venting about it here. If you want to effect any change on here, you'll have to persuade admin to take the time to make that change.
The first question would be, is the site being actively developed or is it just being maintained?
In the past we have had discussions about how we would like to see the forum develop and then asked the Admin to take a look. It is, after all, the users that make a forum.
I think that once a post has been replied to it should no longer be editable or only allowing addendum's
Not letting a user edit their OP is too harsh, especially because the Preview function doesn't even work. The OP wouldn't be able to fix their formatting or other typos. The site has some technical-side problems we all know about. Let's not compromise user experience even further.
Being able to see previous edits, however, would not compromise any UX or beginner-friendliness.