The best criterion for evaluating a piece of art depends on the context and the intent of the artist. However, if the artwork aims to convey an emotional message or visual impact rather than strictly adhere to realism, then "use of color to emphasize a particular area of the drawing" would often be a strong criterion.
If the artwork intends to showcase realism, then "technical skill to create photorealistic imagery" may be more relevant.
Ultimately, the best criterion would align with the goals and style of the artwork in question. If no other context is provided, many would argue that color can significantly affect the overall composition and impact of a piece, making it a valuable aspect to evaluate.