If you have finished your current project faster because of something like Catalyst do you a) stop programming since there is nothing more to do or b) start your next perl project ? If your answer is a, then yes, you haven't learned as much as perl as you could ;-)

More to the point: Nobody anymore thinks of cpan as something separate from perl. cpan is the library of perl. IMHO learning to use it effectively is just as much perl hacking as fiddling with a complicated regex. I know because I still have deficiencies in that part.