where there are so many list items or the items are so big, that they would use too much memory to store in an array

I did consider including that, but by providing a tied array, you're kind of encouraging end users to treat it as any old array.

So they might not consider that doing something like:

foreach my $item ( reverse @array ) {
  ...
}
[download]

Is going to impact performance way more than they might expect.

If it's exposed as an iterator, then it encourages them to access items in a one-at-a-time sequential fashion. They still can slurp it all into an array, but they can't blame you when that eats up all their memory.

Not saying it's never a good idea, but situations where it is aren't going to be that common.

toby döt ink

After I posted it I wondered if my question was too trivial to post. But it turned out to be a great sanity check! I'm now returning a list as suggested. Thank you, Discipulus and jdporter for shining a spot light on this!