It still sounds quite a bit like CGI::MxScreen, but maybe less prescriptive about what other modules it works with. Being flexible can be tough, because an application framework that doesn't assume anything about choice of template tool or validating tool can't offer as much automation to the developer using it. Maybe you can find a good middle ground.

As far as CGI::Application goes, I don't see why you don't just extend that rather than starting from scratch. It seems like it wouldn't be hard to change CGI::App to work with TT2. The HTML::Template integration is minimal.