in reply to OO-style modifiers for 'sub' ?
The really cool thing about Perl 5's object system is that it didn't require adding any new syntax. Admittedly, this doesn't make for the greatest object system, but it's somehow inspiring to know that OO Perl is just the combination of existing Perl structures.
While your ideas could probably be done for Perl 6, I suggest just letting Perl 5 go without it if it means defining new syntax. Though if you can get the same thing in a module, go ahead and try.