It's hardly broken; as with any code, one must understand how and why it works, what are its limitations, and not go about applying it blindly to every situation (eg. a deep compare of nested data structures). In any case, the simple-minded (shallow) approach is usually the one that is wanted for this task, especially when writing in OO-style.

As a further aside, my idiom is usually:

my %uniq; undef @uniq{@arr}; @arr = keys %uniq; [download]

   MeowChow                                   
               s aamecha.s a..a\u$&owag.print