"He is to 'I want' and 'I am' songs what Lee Strasberg is to method acting. It's what he practiced and preached. I think the terms are too simplistic.
I agree. And also, I think it's almost always a mistake for anyone to indulge in gross generalizations such as "EVERY musical MUST have an I want song." That's why I'm very surprised that someone as knowledgeable, talented, and well respected as Engel would be SO rigid about the concept. And I still wonder if anyone ever challenged him by pointing to specific musicals that don't have obvious "I want" songs, and if so, how he responded to that challenge. So if anyone has a story related to that, I'd love to hear it.