Although this thread is a bit old now, I thought I would mention that it is pretty easy to attach an alternate template engine to the controller.
I have easily integrated "Zend_Layout" and "Zend_View" to a SilverStripe build with very little effort (a few hours). If anybody is interested, I can demonstrate.
In my opinion, SS as a templating language has many deficiencies, and going to a pure PHP solution (via Zend) was like a breath of fresh air.