The clue was a little tough - if it had been "The irrational belief that everyone is out to get you" I'm sure its score would be higher... similarly if the Lady Gaga clue were "Ron Galella, et.al."
Agreed. I'm a big Black Sabbath fan, so I obviously had no problem with that one... I've never heard of the Lady Gaga song, but I was able to guess it just based on the clue.
regarding Stevie Wonder clue: he also sang "Faith" which IMHO fits with the definition (although being probably less "canon" for SW). Can you accept it as a solution?