If RPGs are, indeed art, they are probably too hard to capture in a single universally accepted model. Cinema never managed to square this cricle - very simplified example, it's valid to use a technical / aesthetic critical lens to view a movie like The Birth of a Nation and give meaningful insight why the film has artistic merit but it's equally valid to use a social / historical lens to view the same movie and find abhorrent sticking points. It's not that one criticims is 'better' than the other, both critiques can be equally valuable to future artists and critics. Nobody will ever make that exact piece of art again but, after digesting the analyses, they will incorporate the lessons and avoid the pitfalls what went before. That's the true value of criticism.