So if you don't work on core Perl 5, you don't count as a significant Perl contributor? That's pretty limiting, since there are only a few dozen of those people, and Perl 5 is far more than what ships in an individual perl-5.x.x.tar.gz tarball.
(FWIW, adding const to pointer arguments is not about cosmetics, but about allowing the compiler and static analysis tools to better understand the passing of data into and out of functions. This helps detect uninitialized data errors. Here's a thread you may find informative: http://www.nntp.perl.org/group/perl.perl5.porters/2005/03/msg98772.html)
You slight literally thousands of CPAN authors with your standards, saying that they are not "significant Perl contributors", and I suspect you're alone in your assessment. CPAN authors who create and maintain the tens of thousands of modules that make up the CPAN, whether little-used or wildly popular like Moose and Dancer, are making Perl 5 a much better place.