Schenker is pretty questionable anyway. He was a mediocre composer (at best) and it's perfectly possible to create credible multiple analyses of the same piece

Schenker is pretty questionable anyway. He was a mediocre composer (at best) and it's perfectly possible to create credible multiple analyses of the same piece of music. So while it's true that classical style(s) are very specific, it's also true they're all different. Bach, Mozart, Beethoven, and Chopin are not speaking the same language. They don't even speak the same language across their careers. So while there are common techniques - like the idea of elaboration - they're really just the most obvious surface features, and implementing them is not nearly enough to produce decent pastiche. AI/Music research is littered with the the corpses of projects that have attempted to do this. It's an incredibly hard problem - because unlike a board game, the "rules" change all the time, and there is no clear definition of "winning." You can certainly mass-produce musical content in a fairly simple style - say minimal techno - and then cherry pick the best output. But even that turns out to be harder than it seems, and it's not real AI unless you can formally define why some output is better than other output. Beyond some fairly minimal perceptual and psychoacoustic basics, there's almost no research into that. Really, we know much less about music than we think we do. Theory, Schenker included, is a very basic introduction. The interesting bits happen elsewhere, and we really don't understand how they work.