Yes, expressions spanning statements would be unprecedented. And the 'otherwise EXPRESSION;' construct would be an syntax construct spanning statement, which also would be unprecedented. And it's omision doesn't contradict Perls philosophy - I bet Larry's first reaction would be:
What would
print "Hello";
otherwise print "world";
do?
And the smartass who would say otherwise looks at the last expression evaluated, and hence would only print "Hello", as print returns 1, I'd like to point that in such a case:
$x = 0 if 3 > 2;
print "foo" otherwise;
will both assign 0 to $x, and print "foo" - as the assignment to $x is the last expression evaluated.