I would find it odd that so many female Ninjas in video games have such 'healthy' thighs and large breasts (and long hair). But then I remember what companies make a lot of the Ninja based games and who their target audience is.
Still, if you're trying to go sneak around in the darkness in a skin tight uniform, some of these proportions of the girls in these Ninja based games would be a hindrance and give you away quite easily. Not that I think they're going for accuracy.
Well, consider this: Yae's ass is smoking. No, really; it's quite literally smoking. Maybe her un-ninja-like body proportions are just the result of some ridiculous kunoichi jutsu. If this sounds ridiculous or unbelievable, read any number of ninja-based doujins. You'll find your sense of plausibility greatly expanded.
Virtually every other ninja in fiction is too flabby to live, though. No question.
