It's a waste of time whining about what a horrible model she is, I mean, it's not like she's a struggling 17-year old model trying to make it big. She's probably going on 40, hangs around with creative people all days, writing some songs and jumps in as a "statement model" in some show every now and then. No one is SHOCKED when, for example, Galliano put that fat woman in his show because no one even considered she would be a model.
I think you all get confused 'cause she's tall and skinny which makes you think she's aspiring to be a model, which then gets you pissed off cause you think 'I'm prettier then her, why the hell does she get to do huge fashion shows!.
Just realize she's not a working model and understand that you're sitting here writing horribly nasty things about a grown-up woman with a career and maybe husband and kids or god-knows-what, because they´re not looking like a russian 16-year old...
I'm sure every designer who puts her in a show has their reasons, even though we don't know them.