You've had a lot of discussion already, but I might as well give my opinion. It's a resounding 'no'. Pokemon dying in battle makes a Nuzlocke what it is, but that said, not EVERY pokemon has to die. There's so much more to pokemon than fighting for their trainer until they fall in battle. I'm sure a fair few of them would go that way, but what about those that don't get along with their trainer, or don't enjoy battling? Will they all have a moment of revelation or a fatal accident? Getting rid of the 'dead' ones or those you've boxed in different ways really gives you a chance to display their personalities and give some flavour to the story. Also, in my opinion, too much death gets exhausting. I can only pour all my feels into a death scene so often before it becomes routine. Death scenes should be saved for the most crucial moments of the story.