Thank you for your detailed answers, they are much appreciated.
My main concern is with XML-RPC pinging every time a post is edited, which I understand is normally a good thing. The problem comes in for “compulsive editors” who can get penalized for excessive pinging of posts. I have found newbie bloggers to be particularly prone to editing their new posts 5, 10, 20 times in a short time frame, trying to get them just perfect. Because of this I have been recommending that they either turn off XML-RPC pinging altogether, or use a ping management plugin, to avoid any penalties or problems.
Thanks again for all of your help.