I think a huge problem we see today with WP is people trying to push horses into a discepline they aren't bred for. Under most curcimstances, you cannot naurally make a barrel bred horse into a deep hocked, flat kneed, rocked back, pleasure loper. The really nice pleasure horses are bred for just that type of movement. I've had the priviledge to ride some amazing horses, multiple world champions in the pleasure, and they were bred to move slow, deep, and sweeping. They obviously didn't hit the ground knowing how to best use their talent, but training them was pretty straight forward. Teaching them balance helps them settle into a naturaly slow gait. Teaching collection, rounding of the back, and lifting of the shoulders, sets them into self carriage where it is conformationall comfortable for them to travel with a level head.
Once again, the biggest problem we see today is trainers trying to make a buck by forcing an animal who isn't bred conformationally or movement wise for this class. I would be happy to answer any questions on this discipline, friendly or not. Thanks for reading :]