For me, it taps into my childhood wish that I could fly. That's why I love Soarin' too, which I know some people are lukewarm about.
Those are the kinds of experience I like best at Disney--stuff that taps into my too-dormant capacity for imaginative play. Disney doesn't need to wow me with speed, or surprise me with unexpected twists, or make a big production of showcasing its newest technology, or try to be hip. It just needs to remind me of when I truly believed in the possibility of all things, before I became an adult and left some of that behind.