Yes - XML::Generator doesn't separate code from the design, so if thats a high priority, its surely the wrong module to use.

My main concerns with HTML::Template is the lacking support for deep structures. Its a very "flat" way of inserting values and doesn't really do much of the hard work, you'd expect. For one, traversing deep reference structures.

Another big drawback is that you have no guarantee that you're generating valid XML (or xhtml) with HTML::Template.

If designing separate view components (as in MVC) or something of the sorts, using XML::Generator to write smaller components is really straightforward and more reliable. You do lose the ability to use code-less templates, but in this era of xhtml and css, its not as important any longer.