Ah, I see. Personally I think that isn't a strong enough justification, since this choice introduces possible 32/64 bit portability issues and prevents optimizations in scenarios like this. Arrays with >4 billion elements are rare and it would be a shame to compromise the language design for them.
It would also be a shame to end up with an overly restrictively language in future, where large arrays/values need special `..._64` functions (taking 64 bit integers, rather than 32 bit ones).
