Lying Creator: Videos and statements before previews began claimed that the musical was "based on the comics, not the movies." It's actually a composite adaptation of Spider-Man and Spider-Man 2.
Recycled Script: The first version had quite a bit of dialogue from the first movie in it. The second got rid of most of it, but scenes like Spider-Man saving a baby from a fire still seem directly lifted.
Oddly enough, the Green Goblin is given the backstory of Dr. Octopus from the second film, with Harry Osborne not existing at all.
What Could Have Been: Originally, Evan Rachel Wood and Alan Cumming (both of whom have worked with Taymor before) were cast as Mary Jane and The Green Goblin, but the endless delays the show faced getting to the preview period led to both dropping out.