The Cult of the Composer: in lieu of an essay

NB: This is something I want to write as a proper essay, but have no idea about how to phrase. For this reason, I am simply stating the main claims and arguments here, with a view to converting them into an extended piece of writing at a later date.

• Music is like cookery, and different from most other art-forms, in that it is (a) reproduced from a "recipe", (b) generally not seeking to represent anything in particular - and even when it is, does so in a very abstract way
• There are very good reasons for not messing with non-reproducible artworks (such as the originals of paintings). There are good reasons to be careful about how we treat many representational artworks (such as poetry).
• However, when these do not apply, we are generally very happy to modify, deface, and do whatever we like to artworks. Example one: we are happy to adapt cooking recipes, even when they come from very good chefs. Example two: we are happy to deface posters and prints of paintings. (Remember the Joseph Ducreaux meme from a few years back?)
• We should be more willing to carry out this kind of modification for music. By this I mean not just the kind of wholesale changes we already make (e.g. remixes, various classical pieces) but micro-changes.
• By micro-changes I mean deciding that a certain chord is wrong and changing it, modifying a tune slightly, and all sorts of other small changes.
• Composers are presumably good judges of what is good music, but the judgement of the composer is not infallible, and we should be willing to overrule them in cases where we think they have erred (or where tastes have simply changed!)
• See for example these eight beautiful bars in Schubert's Unfinished Symphony, and the two-bar fart that follows them. (from 1:20 in) I don't have a ready suggestion for how to continue the tune, but am quite certain that there are option much better than what Schubert went with.

• Obviously if you are performing pieces for the public then you should make changes only after careful consideration, but this does not mean you should not make changes at all!
• A good performer or composer can definitely improve on an already good piece, and this need not entail any disrespect to the original composer. See, for example, Marc-André Hamelin's excellent cadenza to Liszt's Hungarian Rhapsody no.2 (cadenza starts at 8:26, runs to around 11:40):

• We're past the days in which books are the ideal medium for this, but it's sad that there's no book of "Mozart's piano works, as adapted by __". Nowadays, why not have a website of suggested micro-changes to pieces?
• Try to come up with more suggestions for micro-changes. e.g. I reckon we could improve the descending lines at the climaxes of Finlandia (occurs more than once, e.g. at 3:56)