I wrote my IB extended essay on Alkan, so I know a fair bit about his contributions to romantic music.
There is no question that Alkan wrote a fair deal of crap - but so did everyone else. Alkan also wrote some totally unique masterpieces that would cement his status as one of the most important composers of the 19th century.
Morte of the Opus 15 ‘Morceaux’ anticipates the structural groundwork of romantic pianism. The Trois Grandes Etudes were the first notable examples of etudes for the hands separated and reunited. The bass dissonances in Alkan’s violin duo were previously unheard of, and it is my opinion that this work as a whole is one of the very finest Violin Sonatas composed. The Quasi-Faust movement of Alkan’s Grande Sonata was a landmark in the repertoire, and foreshadowed Liszt’s B minor Sonata. Alkan’s Symphony and Concerto from opus 39 demonstrate the composer’s ability to simulate orchestral textures on the piano and showcase his incredible sense of structure and his skill at large scale compositional form. The Festin D’Esope is probably the very finest theme and variations of the 19th century. Some of his miniatures (i.e, Soupirs) look ahead to Debussy, while others anticipate Mussorgsky (Heraclite et Democrite), and Prokofiev (Musique Militaire)...and there is nobody else in the history of music who could have conceived such an incredible gothic effect in La Folle au Bord de la Mer, or Le Tambour Bat Aux Champs. He also wrote a "Funeral March for the Death of a Parrot" whose bizarre humour would have made Monty Python proud.
Bach was not performed for almost a century after the composer’s death until Mendelssohn conducted St Matthew’s Passion in Berlin to great success. The late sonatas of Schubert were virtually unknown until Schnabel championed them in the 1920’s. In both cases, great music was overshadowed by the fads of the time.
Alkan has been largely overshadowed due to the man's reclusive habits during his life, the music’s technical demands, and the difficulty that listeners have adjusting to Alkan’s unique and often puzzling aesthetics. Still, a new generation of composers, pianists, and music fans are becoming exposed to Alkan’s best works through the recordings of such pianists as Marc-Andre Hamelin, and by simple word-of-mouth. History has been cruel to Alkan and his music, but through its sheer quality, and creative genius, it will eventually receive the recognition it deserves. One day, Busoni’s claim will be commonly accepted and the name “Alkan” will be spoken in the same breaths as the titans of 19th century keyboard literature, Brahms, Chopin, Liszt, and Schumann.