Yes, I do my editing on pending messages.
I too did some simple tests today.
- I confirmed that using DELETE+SHIFT+RETURN does work to remove a paragraph return and replace it with a line wrap in word and Outlook but does NOT do anything in the new editor.
- Likewise, DELETE+CONTROL+RETURN does nothing in Word and Outlook for me, but does accomplish the intended purpose in the new editor. I am using Firefox, Windows 10 and Office 365 v. 174 on a Lenovo Thinkpad Ultrabook.