While I was not the one to downvote the node, it is my guess that the reason may have been because of the controversy that the question could arouse. In its own way, that question is as flammable as any other than I am aware of, mostly because the approach decided on is mostly a matter of personal preference. For someone new to using them, or still trying to decide on which one to try, comparing them can be quite difficult, even without the "mine is better than yours" arguments that sometimes ensue.

As to it having been done before, a search for "templating" gave me the threads Best templating system?, an opinion on templating systems, Here's some more discussion on templating systems, Web Application Frameworks and their Templating Engines with a Comparative Study of Template and HTML::Template, and Choosing a Templating System, among others, which would lead me to suggest that it had been done. Not that it wouldn't be bad to hear reasons why/for/against them, just that it seems like it has been done, and might be one of those polls where the required fashion statement might be designs in asbestos.