I have been looking through Jeremy Keith’s collection of design principles, and one I’ve tended to obey is the Rule of Least Power, even though I didn’t know it had a name. It is also the reason for Atwood’s Law.
HTML is the suitable language for most of what’s on the Web, but that is often generated by some other language. If we apply the rule to the templating language, our tendency will be to choose one that provides less power, not more. I look for templating languages that do just enough and aren’t tied to another, more powerful language.