I was kind of like "wait a second, just when I think I have things figured out you're telling me to let the horse do whatever he wants!?" So thanks for clearing that up.
I have bought a few horses that seem to put their heads in the air whenever they feel bit contact and it took a little while to get them to trust me that I could make contact and they wouldn't have to put their heads up. I think that is from past riders being heavy handed.
Now gaited horses I am new with, so I am still figuring out what kind of level of collection/head set I am aiming for. Because my Fox Trotter tends to put her head up and nose out too (when gaiting).
But I think the basic concept of hollow vs. rounded is easy even for a beginner to understand. And I think that is what the OP was referring to when he/she said they were told the horse noses out too much. At least that is what I see in the photo- a hollow horse, correct?