Analogy of the day:
Web designers are bus drivers. They’ve got a steering wheel and a gear shift (XHTML+PHP+CSS) that they know how to use to arrive at a good solution for their clients.
Magento’s XML-based templating system is like sitting these bus drivers down in a plane cockpit. There’s the potential for a way better design solution for your client. But the bus driver doesn’t even know what button to push to make the plane start rolling forward, let alone get it into the air.
It’s a stretch, but that’s how I feel right now. I don’t know the first step to getting this Magento templating system to work.