One thing I thought about was, if adding entire Webpages with all their inline elements to the media library wouldn't be a nice feature. Not that it would make much sense in the daily blogging business (why mirroring the internet).
But weblogs are a kind of diaries or even research tools. And as such they could be valuable archives for oneself in the future. But there is no way, all those links contained in the log would work in a few years, making the whole weblog a whole lot less valuable.
Perhaps even the script could fetch all webpages referenced in an entry when posting it, saving the contents of them in the background.
One can develop this idea much further but I think it's clear, what I intend to say.
Speaking of parsing the content of new entries, how does your system work? Are media library items statically linked against the blog entry or is it possible to change the position of an image in the directory structure or to change its name without disrupting the post? Does the media library keep track of all the blog-internal references? Just curious