"Why change?"

Because a lot has changed in the twenty years Perl has been around.

Machines have got much faster. The WWW has become universally accessible and universally used. But mostly, the users and designers of Perl have discovered that it's greatest strength is the programmer productivity it provides.

So now is the time to make full use of the experience gained through those twenty years, to re-engineer the language to capitalise upon the languages strengths, clean up some weaknesses, and further enhance that programmer productivity.

It is time to recognise what it is about the original language that provided that programmer productivity, and what about it was a barrier, and use that knowledge to redefine the language devoid of the constraints of backwards compatibility.