I just noticed this discussion and it's a difference of opinion I've also had with the core P6 devs: integers and rats are the same. That being said, integer math should be much faster than rational math and I don't know how difficult it would be to special case the code for that.

On the flip side, by restricting this behavior now, they wouldn't need to take it away later if it proved problematic. I expect that heavier usage of the language over time is what will impact decision making here.