^^I think it's unlikely to cause a negative palmar/plantar angle from alone... unless you do a Strasser type trim & remove heels all together. If you don't invade the sole plane, don't allow the toes to get too long, I think negative plane is not a big issue.
But then why do some horses just "have it?" I guess by that I mean, when you start looking at photos of horses, especially on their hind feet, a lot of them have a bull-nosed shape which suggests negative palmar angle. So it that just from not backing up the toe enough? Or???