The main thing that leaps out at me is the name: in my humble opinion the concept is not so extraordinary that it merits its own top-level namespace. CGI::REST would be more reasonable.

Looking more closely, the $1, $2, $3, ... construct is pretty fugly. I would recommend you investigate what @- and @+ do, in order to build something that works to any arbitrary depth.

The dispatcher package is pretty minimalist: this forces a lot of make-work code into the renderer packages. I think it is important to add more infrastructure in order to make the renderers as simple as possible to write. You need to refactor agressively and pull as much repetitive code out of the renderers as possible.

The module would be entering a fiercely competitive mindshare space. There's a lot of modules out there that already do this sort of thing. You'll need to have a few very good real-life ready-to-run applications that people can tinker with and see what happens.

It would also be a good thing to have a look at what's out there already and discuss how your module is similar to others, and how it differs.

In any event, feel free to publish it on CPAN.