It wouldn't be. In this case "best way" would be defined as something along the lines of maximizing total happiness.

Still, rather than having one universal best art, the best approach is to have different peices of art to apply to different people. There may be a universal best piece of art for one person, but I imagine they would still want variety.

I suppose you could try to define away all subjectivity by appealing to utilitarianism, and maybe a post-singularity optimiser that can simulate all brains to gauge their reactions could create a perfect peice of art by those standards. Its still useless for discussing matters in the present.