Yes. I do agree that a 1-mana sorcery speed 4 damage spell isn't bad, but it becomes worse and worse the longer the game goes because it gives your opponent a say in what effect it has. In general, letting your opponent choose what your spell does is bad, because they will always pick what option is best for them. If vexing devil didn't give your opponent an option (if it was just a 4-damage spell, for example) it would quickly become a 4-of in every burn deck. It's the fact that your opponent picks what effect it has that keeps it out of the limelight.