You could say the same thing about Beethoven's piano writing, too. Maybe the pupil emulated the master a tad too much?
P.S. For sheer technical accuracy Hamelin (I've been fortunate to watch him dispatch those Chopin-Godowsky monstrosities in person), Michelangeli and Pollini have Zimerman beat. And of course you've got yuge technicians like Hofmann, Friedman, Lhevinne, Cziffra and Horowitz who like most old-timers didn't care much about the wrong notes and often had to do without editing!
P.P.S. Dvorak is another one (in)famous for his unidiomatic piano music... but who gives a crap when it sounds like this:
That 6th Humoresque has been one of my desert islanders ever since I discovered it back in high school. Just drop-dead gorgeous, and infused with "unpretentious beauty" by Firkušný, too (that quote is from the great man himself - still have his edition of the bulk of Dvorak's piano output).
I'm convinced by your nonstop name-dropping that you're telling the truth for once when you say you had formal instruction in piano, but you apparently spent more time sucking up to the big shots than studying the scores cuz it's hardly a secret that "the summit of tough Brahms" is the Paganini Variations.
Which of course gives me a good excuse to post this, probably Michelangeli's single greatest technical feat (yes even more so than his justly celebrated Gaspard):
That's
live, and knowing him most likely unedited.
I can't help but question the wisdom of practicing 8-10 hours a day even for obsessive pros like him, but nobody can say he didn't get the result he wanted.