As I've said before, I think she has a lot of talent but needs training! I also think she's going to win, which may do her no great favors in the future if she can't eradicate the bad habits she has and develop the discipline I think she needs.
I'm not the biggest fan of Jessie, but I do understand what is meant by 'tired tricks' that some training often tends to instil in people. And I speak as someone who has been trained. Some tricks include - ways of singing (bright, vibrato, with lots on an 'ee' sound) that is arguably a trick that tends to make everyone sound impressive but the same - sharp, clear acting movements that are sometimes more about style than truthfulness - certain hand gestures and movements - some kinds of phrasing / speak-singing etc
All of these are things that the best musical theatre performers grow out of, but you see them time and again among younger trained performers (or untrained performers who are trying to 'copy' people they have seen on stage) and I would agree to some extent with the argument (at least in theory) that you can discover a fresh talent and give them intensive one-to-one training to get them up to a high performance standard that still keeps their freshness. Ultimately, musical theatre courses have to fall back on these because they need to polish people for performance but don't have the time to go much further than that individually with their students, so I think you see the best musical performers once they have been out of drama school for a couple of years and have really learned how to perform.
You know, I think it's these tricks that have undermined Rachel and Sarah a bit - the panel loved them, but lots of the audience just seemed to find them a bit contrived or limited in their acting, and with pretty, controlled voices that again don't really grab you. I reckon they'll both be really good in another few years but they still have to learn how to balance the best things learnt from training with getting back to a truthfulness and engaging style of their own. For me, Sarah kept taking on notes to some extent and was one of my favourites, but still never quite rang true when performing -- yet.
The best MT performers (just in my opinion - so please don't jump to attack me for this!) are those who are experienced but still have a unique, natural, sometimes raw / vulnerable quality - like Ruthie Henshall / Maria Friedman / Anna Francolini / Scarlett Strallen / Lea Salonga
PS Am I the only to think that it's a bit silly talking about training vs not training when a lot of the 'untrained' girls have probably had singing lessons or been in a choir? It's perfectly possible to get just as much training not going to drama school by getting a good singer teacher and going to dance and drama classes!