butterandjam
We've already got both facilities.
If you want your own post deleted, just "report" it to GN and ask them to delete.
"Preview Message" appears below everything you write. The purpose of clicking on "preview message " is to enable editing before posting.
I do get that, but often forget or find it a faff! 
I’d like a proper, after posting, edit facility!
The problem with preview is if you use immediately after preparing your post, your brain often reads what you think you wrote, rather than what you actually wrote.
