Yep I'm constantly being told my horse has fantastic conformation. He SO does not! Monty has upright shoulders and pasterns, long cannons, a long back, would like some more substance to his hindquarter... the list goes on and on. I find that a LOT of people really don't know a lot about confo and they think "ooo pretty horsey, must be really well put together then!"
I think a horse with fantastic conformation is a very rare thing, so much so that most people don't know it when they see it. There is nothing wrong with a horse that has lots of faults, lord knows mine has plenty of them! That elusive thing called fantastic conformation is very highly in demand because it lends a horse to versatility, and it can turn its hoof to whatever you want to try, but ONLY if it has the right temperament.
Temperament and passion are SO much more important. Conformation only dictates what the horse is PHYSICALLY capable of, and all the perfect conformation in the world will not make up for a lack of confidence and/or passion. My boy, for all his faults, is a fantastic, talented eventing horse, and has cleared 4' - clearly a case of heart over conformation for sure, but that doesn't mean I shouldn't be jumping him.
This mare, with her upright-looking shoulder, may not excel in disciplines where reach and length of stride are required (such as dressage, jumping, and maybe speed events), but it shouldn't affect her too terribly, except that her stride may be a little short and choppy. As I said, heart is far more important.
She looks like she's got the right temperament to excel as a trail horse (competitive trails maybe? That is as much a performance discipline as any other) and I don't know a huge amount about western but maybe there's something that would work for both of you, and that she might be brilliant at.