Just looking at the final parts...
Petrushka and particularly Mereaux's Etudes are way too early; they will be massive spikes in difficulty.
S. 137 and 140 are also way too early.
What's Le Festin d"esope doing out in front of the rest of the Minor Keys Etudes?
You've listed the Douze Grande Etudes twice: #159 and #164.
I'm sorry, but what the f*** are you doing with #168 and #169??? The Major Keys Etudes are significantly easier than the Minor Keys. In fact, Among pre-1920 repertoire that I am aware of, the complete Op. 39 Minor Keys Etudes are among the top 3 pieces in terms of difficulty (behind only the Mereaux Etudes and Liszt's S. 464.)
What are the "Pseudo Concertos"? If by Liszt's you mean one of his Sketches, then it belongs far higher.
The Godowsky Studies are much easier than many of the things you've listed here.
Finally some Saint-Seans, though I'd argue it's a bit too late.
Le Preux is not Alkan's most difficult work.
Prokofiev's Op. 2 Etudes are pieces of cake compared to the works around them...
WTAF are Liszt's Gnomenreigen and Waldesrauschen doing at #194???
Alkan's Op. 76 at #197 despite Op. 39 being #168...
Ravel Left Hand Concerto is easy compared to these other works...
Why 25/2 in Octaves instead of Brahms' version, which is 3rds and 6ths?
S. 464 is way too early.
Alkan Op. 33 isn't that difficult compared to many works that you're including here...
El Contrabandista is way easier than literally anything in your last section.
#215 and #216... what?
Opus Clavicembalisticum (#215/216) IS Sonata no. 4 (#227)...
Archimagicum is the hardest thing on your list.
A few things you notably left out...
No Brahms?
Missing a lot of later Liszt works, and some in-between the ones you included. A few examples:
La Clochette S. 420
S. 700i and S. 700ii
S. 138
S. 100
More Saint-Saens...
The only atonal composer you've included is Sorabji, who wrote pieces that were relatively easy compared to other atonal composers. Examples include Ligeti, Xenakis, Ives, Finnissy, etc.
You included a total of just 12 Scriabin pieces (across 3 opus), and not a single one of his Sonatas?
You included a list of Scarlatti's Sonatas (roughly from easiest to hardest) without a single one of his works appearing in your chart?
A few other suggestions...
Clarify the composer on as many pieces as possible.
Change "The Bombardment of Warsaw" to "Revolutionary." It's a much more common name for 10/12.
Chasse-Neige as the hardest Transcendental is something you don't see very often...
Include some easier atonal works to help transition from Spanish Fantasy to Sorabji; atonal works require very different technique.
I didn't notice any Bach in the list (neither J.S. or C.P.E.). That should be fixed.
FFS Use a Word doc, not Google Docs.

Hope this helps,
Liszt