Hm... That's a good point. I wonder if there's a time limit on being Returned? If you've been dead a century, could you be Returned? a year? a day? an hour? a second? The only Returning we've seen so far was Lightsong's (and that one we learned about secondhand).
If there is a time limit, it implies that the Breath does eventually leave a dead person. If not, then yes, I agree that death is ends-neutral.
Also, to be clear, there is a distinction between whether people do Return long after death, and whether they can return long after death. I suspect that people who are given the chance to Return are given the chance once, when they die, and that's it, but does not necessarily preclude the ability to Return later, just the opportunity.