The sorting part isn't hard, IMHO: you could translate the thing into a sort-of-Schwartizan transform where an array element would be either a key, or a coderef, and sort that fairly nicely.

Finding a good way of passing all that data to a Perl5 routine, however, would be a challenge.

Which, I think, is why Damian chose the theme. I don't think his point was the wonderfull multitude of things his sort is going to do, it's all the wonderfull ways of communicating with subroutines that the new syntax will make possible.