Personally I'd /really/ like to see DOES become more useful before 5.10 comes out. I think its a perfect opportunity to fix a bunch of problems. IMO, it should be usable in subroutine form, BUT still respect @ISA for blessed objects, it should handle the question of "can I dereference something in a particular way", and third it should answer "is this a compiled regex". I imagine that something like the following results

UNIVERSAL::DOES(sub{},'&{}')              # return true
UNIVERSAL::DOES(qr//,'qr//')              # return true
UNIVERSAL::DOES([],'@{}')                 # return true
UNIVERSAL::DOES([],'The::Funky::Chicken') # return false
UNIVERSAL::DOES([],'UNIVERSAL')           # return false
@Bar::ISA=qw(Foo);
UNIVERSAL::DOES('Bar','Foo')              # return true
@Bang::ISA=qw(Foo);
sub Bang::DOES { return 0 }
UNIVERSAL::DOES('Bang','Foo'}             # return false
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I actually have a patch to universal.c for this behaviour on the brew right now.