Maybe it is just me but looking at the pictures in the press kit, she doesn't seem to be miserable. In fact, just the opposite. If she wasn't missing her snout/upper jaw, she appears to be acting just like any other dog.
If she's able to somehow eat, be happy, playful, etc, I wouldn't put her to sleep. Without actually seeing her in person though, I'm hesitant to make any kind of judgement (though it does anger me she was allowed to whelp a litter - her immune system has already got to be taxed from fighting off infection attempting to take hold in an open wound, and they let her get pregnant??? And she still isn't spayed, she was wearing a diaper in the press photos, doesn't going into heat, pregnancy, birthing, etc, all tend to suppress the immune system? If they want to keep this dog alive they should be looking at the long term. I know surgery is rough on the immune system, but...geez).
I just can't imagine what life would be like for her not being able to smell. That's the primary way a dog experiences the world. It's like if we lose our vision. It's devastating. We can get by without it, of course, but it's a huge alteration to our daily life. And there's more...how do I say it...substance, maybe? There's more substance to our lives? We do more than eat, play, sleep, poop. Well, most of us, anyway.
I don't know. I can't honestly say what would happen if this was my dog. I think this is kind of one of those one-in-a-million things. It's miracle she wasn't killed instantly, a miracle she didn't bleed out or die from the trauma minutes/hours later, it's a miracle infection hasn't taken hold and killed her, it's a miracle the complications that has to have brought on hasn't killed her. If this kind of injury happened to any one of our dogs I very much doubt we'd be in a situation where we'd even have to decide whether to PTS or not.