My experience was not that the Iliad was hard, it was first learning to read Greek
Moving from Attic to Homeric took a little doing, for those who survived first-year Greek. We actually read the Odyssey rather than the Iliad in second-year Greek, since the vocabulary was somewhat easier. I did finish the Odyssey, but only read the first eight books of the Iliad.
Now Aeschylus and Pindar, that’s another story....