The question is whether the Perl 6 guys want to pursuit this. It does sound to me like a great idea, but with a project, you always need to prioritize things. As you can see, I think Perl 6 development is under other pressures that are more important, in order to form the base of the language, as well as the VM.

As whether it is getting difficult for Perl 6 to do this, comparing with Perl 5, my guess is not, and it is probably getting easier. With the VM concept being introduced, it become a perfect place to add this sort of control.

Look at Java's experience, it should be something "addable" at a later stage.