Yes, it's a no-no, especially so for a core module.

Keep trying perl5-porters; sometimes people get busy and miss messages. You will generally get more comment on your patch if it is included in the body of your message, or an uncompressed attachment. Also try putting [PATCH] in your Subject.

The listed maintainer of the CPAN module is ilyam@cpan.org, but the change really needs to be accepted in the core before going in a cpan version.

Does Data::Dump::Streamer do what you need? You might consider it instead.