I think the more-tag should simply expand the message (in index.php), instead of redirecting to the comments page.
And the comment editor should, when the 'add comment' link is clicked, be added just after the message, instead of in a new page.
And the perrmalink should point to a page where the entire message are shown. Now you only get the first part, if there is inserted a more-tag. And, at the bottom of the page, there should be the usual links - add comment, print, etc.
This sounds pretty good. The different display views really need an overhaul. Unfortunately based on the way it was written its not necessarily an easy fix.