Did anyone yell at you because the experimental signature implementation breaks anything?
Yes they did as a matter of fact. (Off the top of my head, lvalue subs got broken).
It's just syntactic sugar injecting pure Perl code in the body
No it isn't. Both perl (5.26.0 onwards) and cperl added specific new ops internally to support signatures.
Anyway, I'm not arguing with you any more. I've explained at great length to you various technical and logistical reasons why perl hasn't been getting lots of new features, and you just keep repeating your original complaints.