Oh, okay. I guess I misunderstood the OP. I thought that he named the variable $return because it was unimportant to his question.

I can see that if you speculate about the bigger picture, the name of the variable is important:

sub isAllDataValid {
   my $return;
   if( ... ) {
       $return = thisTest(...);
   }
   elsif( .. ) {
       $return = thatTest(...);
   }
   else{
       $return = theOthertest(...);
   } 
   ...
   return !! $return;
}
[download]

And the normalisation of disparate returns is relatively unimportant.