HTML::Template is another language - exactly the same "issue" as you have with XSLT. The only difference is that XSLT is more powerful, and perhaps more cleanly designed, having learned from 20 years of development of DSSSL, which XSLT is based on.
There are some pretty good perl modules for doing XSLT. Notably XML::Sablotron, XML::LibXSLT and XML::Xalan.
Basic XSLT is incredibly simple. To style a particular tag (say <foo>) as bold, you just use: