Good observations.Listening to some of them perform in front of the audience, a lot of them sounded off key at times, used more throat than diaphragm. You can tell some of them need voice training badly. Rachel is young and definitely needs more vocal training. When I lived in LA, my roommate was a talent scout. We use to watch American Idol together. She had me not look at the performance and close my eyes and listen to the voice only. It's no wonder blind people can get a true sense of certain things in life.