I can see how this would be useful, however, as you pointed out, its rough, and not production quality IMH(umble)O.

I can also see a reason why not to use CGI.pm, (a very small script, and you can take everything out of %ENV). Horses for courses, whatever works for you, right?

To productionise it, i would start with actually using CGI.pm, and a templating solution. The downside (or, "On the other hand"), this introduces complexity, which is in contradiction to the simplicity shown above.

As i said, whatever works in your situation.. as long as you're aware of the pro's and cons.