Perl::Critic is great and I use it for all my modules. However, it's only advice, and can be configured to the author's tastes. The intent of the RequireArgUnpacking rule, which is what you're seeing here, is to catch subroutines that use @_ throughout their code instead of unpacking it into local variables at the beginning of your sub. However, your code is doing that here, so the rule is simply being a little too trigger happy. This is exactly the reason you'll find  ## no critic (RequireArgUnpacking) scattered throughout my code, and that's my advice for you in this case.