Auto loading modules for a plugin system would be pretty valid.

I must beg to differ. Or at least, I can't think of a reason :-).

• Listing modules in a location, for a user to choose from, would be pretty valid. I suppose.
  But what if a plugin didn't appear as MyCompany::Plugins::PluginName? What if it was ThirdParty::CompanyPlugins::PluginName?
• Auto-loading modules when required would be pretty valid.
  But that's just

  eval "use $module()" or die "Could not load plugin $module, error: $!";

• Auto-loading modules listed in a config file would be pretty valid.
  Or just require() a file which use-s the ones you want. (Hey, perl has a syntax, why invent another?)

But why would you want to auto-load modules in a location? If you want to temporarily stop using the module, you'd have to uninstall it.