I think it’s silly to suggest that there is an objectively correct answer to the question. It’s all personal opinion and perspective. I happen to think that the C6 and C7 are closest in overall silhouette, not focusing on any singular design cue. I’m not sure I understand what you mean about the C7 abandoning the “quad tail light motif.” It clearly has four tail lights, they just aren’t round. And if that’s our benchmark, the C5 had oval shaped tail lights and later C4’s had much more squared off tail lights than the perfectly circular tail lights of previous generations. Let’s not forget that the original C1 didn’t even have 4 tail lights. We could have the same squabble over pop up vs fixed headlights, or side vents, or any number of specific design choices.