I'm all for this option; however, edit conflicts would be difficult to avoid on heavily edited pages. User authentication is another obvious problem; my preferred solution can be discerned from my .sig and the attachments to this message.
I think the suggestion is just for them to be able to send a comment that would be stuck on the comments page - another user would then at some stage integrate that into the page text. You see this happening already sometimes, people drop by, say they don't know how to work wikipedia, but ... is wrong with the following page.
Steve