This would contravene the training-wheels nature of Go. Also, Perl-style (ir-)regular expressions, despite their popularity, are not a worthwhile abstraction I

This would contravene the training-wheels nature of Go. Also, Perl-style (ir-)regular expressions, despite their popularity, are not a worthwhile abstraction IMO and thus should not be enshrined in the standard library of programming languages, even if you want them in your library eco-system for end-user facing API compatibility.