Somehow I didn't see much in the way of uniqueness in the fan art above, but at least it looks great. I imagine this is originally vector art based on the lack of outlines (rendered as an image of fixed resolution).
I strongly suspect that the image was traced directly over a 3D model. I do agree that some "uniqueness" is lost since there is no room for expressive lines you get from drawing from reference or from memory but I overall like the fidelity to the 3D model.