Sounds like a good idea. (Specificly, I'd like <readmore>s to show up as <hr>s when they're being looked at directly.) Or, we could do what livejournal does, which solves this problem (though it isn't as much of a problem there), and gives the user more control. LJ has an <lj-cut> tag, which can look like <lj-cut text="Example cut...">stuff inside the cut</lj-cut>. That renders as ( example cut ) in a cutting context, and ( example cut )
stuff inside the cut
when not. (If there is no close tag, then the cut is taken to last until the end of the post.) That would be significantly more work to implement, though.

Oh, and welcome to the team, Aristotle. (/me takes a moment to bask in the minor glory of a self-coined term catching on.)