That would appear to be a major global change so I hope everyone will have the opportunity to discuss this issue.
Personally, I think everyone should have the right to edit and/or delete their posts and, if they are the thread starter, to delete the whole thread. I have deleted topics I have started for what I consider to be good reasons and, for a good reason, I would like to delete a post on a thread which has been closed (not on this forum) but find I cannot as it's been closed.
These reasons are varied and personal; just as anyone else's reasons might be for doing the same thing.
Cheers
Whirls