Why is it 90% superhero?
I'm sure the Celebration of 75 years books cover a lot of style changes in comics but there's better examples.
Why not something like a collection of a famous golden age artist like T'aint the Meat collection of TalesFromTheCrypt stories or one of those Fletcher Hanks books.
Or when bronze age started to deviate from the campy silver age like original Swamp Thing or something from Vertigo like Sandman.
Or a look at new paper comics like Peanuts or Blondie
Or a look at western inspired works like Astroboy
Or an adaptation of a story from a different medium to compare pros/cons of comics like the Twilight Zone comics or Trick R Treat or The Hobbit comic
Or hell a biography of a historical tragedy like MAUS. Hell what kinda college would NOT go for Maus?!