I recommend extending CGI::Application with another class and making all your CGI::Application classes inherit from your new base class instead of CGI::Application directly. You can then define your own set of methods (or just a single one) that can be a bit more clear. For example, you can initialize your %hash there and then make your own accessor, hash(). That way, you don't have to use "param" with everything (which can be vulnerable to typos in the keys you pass it). For example, if you call:

my $hashref = $app->param('hush');

And param "hush" isn't defined, what happens? If you make a method to get it:

my $hashref = $app->hash();

If you misspell the hash() method call, you will get a real perl error.