“Wouldn’t you love it if FR allowed you to edit posts after you click the Post button?”
Depending on how that was done, you might end up with a lot or replies that didn’t make sense. (Well, Ok, that happens now.)
Folks might have to keep checking the original post to see if it had changed unless there was a change notification mechanism.
I have seen that feature abused on other sites that allow it. You post something outrageous, someone else replies, you go back and amend your post to make the replier look like a moron.
You would need to have a fairly narrow window of time to allow a change. To avoid the above trap you just wait until the window elapses before you post.