While your proposition may have some intellectual "completeness" to it, there is enough line noise in Perl without taking what is a perfectly understood concept of labelling subroutines / functions / whatever with a descriptive tag. Now any reasonable programmer seeing a code fragment like:

sub foo {
#
# some collection of statements that do foo
#
return $status
}
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will be pretty clear what it is doing. Why complicate things by replacing a perfectly good word (sub) with some cryptic symbol? This is Perl, not APL. How does it advance the language, or provide needed features to the language?