I'm with OS on this one. The back end just doesn't look right, and I don't know how to fix it, but something just looks ... wrong. IMHO, the trend, the eyeline, the flow of the eye across the back of the car should be horizontal. 10 deg up, as OS suggests, may even be too much -- 10 deg down maybe even better? Don't know, but I'm sure it'll be offered as an aftermarket option sooner or later.
Dan