With you on Schumann. Was Mendelssohn in there? Scarlatti? I forget."We asked 174 composers ..." Yeah. Depends who you ask. And as a BBC we, ...
If Debussy and Stravinsky are Top 5, and that's reasonable depending on your frame, then I think Ligeti in Top 10 is correct.
But Ravel at 9 with Schumann at 49? This calls the whole 174 into question.