I feel like I could pretty easily map Woodduck's artist-centric views on this subject onto the way in which I'm arguing for the "subjectivist" side. To me, what Woodduck says--to take one example--about Mozart's mastery of form and melodic inventiveness could be slightly rephrased to acknowledge the subjectivist side by noting that Mozart's use of form and melody move us (intellectually, emotionally, aesthetically), which then triggers in us the evaluation of his mastery. My only complaint with what he says is that it glosses over this causal chain in which the objective features of the music interacts with our subjective minds and based on the positivity of that interaction we assign values to Mozart and his music.One of the things that comes across very strongly in Woodduck's post is the view of the artist. It's one of the reasons why differences of opinion arise in this subject: the amateur consumer (like me), the musicologist, the musician, the composer etc all bring not only different perspectives, but different levels of commitment to certain ideas. I have no investment as an artist; Woodduck has an overwhelming investment as an artist.
I do think it's unquestionably true that some artists are more skilled at triggering this causal chain than others are, but this very much goes back to SM's point about polling and such in that what we're talking about is greatness is essentially a poll on how many people have been moved by an artist and their work; and when that poll reaches large enough numbers we easily start taking for granted the subjective component in all of this and simply project our collective internal judgment of greatness onto the object (the artist and their work) itself.
It reminds me a lot of what ET Jaynes coined as the mind-projection fallacy, or the innate human bias to project the contents of our mind onto the objects that trigger the state of mind in us. Eliezer Yudkowsky wrote an article on this using popular "alien invasion" fiction as an example, in which aliens, who would have a completely different evolutionary psychology than our own, would often kidnap beautiful women to breed with. The point was that the authors of such works considered "beauty" an objective feature of the women, something that even aliens would recognize, glossing over the fact that our perception of feminine beauty stems from our own species' unique evolutionary psychology. Here's the full article for anyone interested: Mind Projection Fallacy - LessWrong I think something similar is at work in these types of discussions.