Yeah, exactly. I'm glad that it was one of Rowling's requests for Potter in the Parks. While Universal can hire pretty amazing walk around characters, I don't wanna see that with Potter. That, and the actual characters are seen in Forbidden Journey in the queue and in the ride "in person", and portrayed correctly, so it would be odd to see a look alike right after the ride.
That's why with my idea for a Care of Magical Creatures experience, it would be with Hagrid's assistant, and the focus would be on the creatures.
EDIT: Maybe that shack will feature a fastpass/time return ticket machine, and it's featured there to be hidden from the elements?