I think that namespace would be a problem for a few reasons:
- we don't know if we'll end up using it for something
- it's very generic
If someone wants to create the same thing ("hey, I want a mailman in Dancer too"), you basically get a clash. Now you'll have Dancer::App::Mailman and Dancer::App::Perlman and Dancer::App::Mailman::Faster, etc.
The best approach, IMHO, is to give your project a name (like "mailman" is the name) and use that. This is what Starman, Twiggy, Dancer, Mojo, etc. do. We all give our projects names and release them under those names.
Also, another general note: web applications don't really fit the CPAN structure. I think every web framework (including Dancer) gets this wrong. Our installation tools are not suited for this type of program. We do our best (sort of) to allow easy encapsulation but it's still the wrong approach. I don't think anyone figured it out yet in Perl-land.