All theme parks rely to one extent or another on sets and I think that a good deal of the charm of visiting these places is the scenery. The thing about MGM-Disney is that the theme is movie-making and so you get all of the scenery but they also let you see that it is not real. Since they don't have to hide the fact that what you see isn't real, (in fact, they don't
want to hide it) it frees them up to do really impressive stuff.
The above is a scene from the grandstand at
Lights, Motors, Action!™ Extreme Stunt Show
What I like about the view is that from this vantage point you can see the Hollywood Tower Hotel, the top of Mann's Chinese Theater, Mickey's Sorcerer Hat
and a Mediterranean village.
There were a couple of sets where (from the right position) it looked like you were in Manhattan or San Francisco:
The effect is pretty convincing, but there are flaws: You can see the shadow of scaffolding from the back-side of some of the set on the face of a couple of "buildings"
The SF set is really good. The girls are standing next to and even touching this painted wall and it still looks like they are on a street in San Francisco.