I believe it happened right around March 30. I like the change because I used to hate editing a post for a simple typo, then having to wait forever for it to repost. By the time it reposted, many times it was dated, as orhers may have replied the same answer, or the thread was just old already.

However, I agree with you, that there were reasons for the delay, and hopefully they have something in place (perhaps the 'report this post' button) to prevent the scenario you mentioned. I had also heard before that the reason for the delay was to prevent moderated people from making certain posts. It was said that a moderated person's first post would have a delay, but then they could edit it and it would repost instantly, making it easy to stir trouble. So the editing delay was in place for everyone, moderated or not. I don't know if that was a true reason, but if it was they must have found a way to fix that now, so that a moderated person's edited post is still moderated but a non moderated person's edited post goes up instantly.

Only theories and hearsay on my part. Maybe admin will chime in, but I don't expect it