Provocative reddit thread. I think this "Perl is Dead" meme is way overblown. Much fewer lines of code were written in Common Lisp or Prolog, but they are far from dead. I'd say Pascal is deeper in the grave, but that is another story.
But in terms of specific CPAN modules that should be repaired -- any idea on how the testing tools could generate a prioritized "TODO" list for anyone motivated to try and fix them? I know there is a the CPAN River -- a list of the 3000 modules that are listed as dependencies.