Below contains some extremely freaky geekery… proceed at your own risk.
I’ve been playing with XSL recently, and was thinking that there really should be a blogging platform that uses XSL as its template language. We could get away from all the MT tags, all the funny TextPattern stuff, and WordPress could have some templating language outside of PHP. It doesn’t even have to be slow. Each type of page (home, archive, individual, etc) could be configured to put certain elements into the DOM, and you could then associate each template with an XSL file (like you do with TextPattern today).
It could be a lot of things, especially if the major tool providers could agree on a schema (I’m thinking Atom with some extentions for category lists, etc). Templates could be traded among systems. If you create a new tool, you’d only need to use DOM/XSL and you’ve got your templating language, and if enough of the tools support it, you know you’ll be able to find people who know. The people who know it, as an added bonus, are not limited to just blogging. XSL is used in other tools and industries.
Of course, I don’t have the time to do anything about any of this, but it sure would be fun, wouldn’t it?