I think the answer is: People expect better from Disney. Disney, at least classic Disney, evokes a state of mind and touches the heart in ways that Universal cannot. The name "Disney" is synonymous with "magic" for many people, whereas Universal is just another movie studio. So people expect greater things from Disney. Universal, while a good park in many ways, is kind of a mess and kind of a mix thematically, because Universal really doesn't have the film and television legacy that Disney does. It doesn't have its own Mickey Mouse, and it never had anything close to a Walt Disney. So it has to bring in outside stuff just to be able to operate, to offer anything to customers. If it had to rely on its film legacy alone, it'd sink. And since it never had an original plan, like Disneyland with its "Adventureland", "Frontierland" and "Magic Kingdom" domains, it doesn't matter so much where it puts its attractions. Maybe that's why it gets away with the stuff you mention.
If I may digress: I have a real fear that WDW and Disneyland will start becoming more like Universal by bringing in stuff the Disney Studio didn't create or adapt, like Marvel or Avatar. The Disney magic is in danger of being diluted by such stuff. And unlike Universal, Disney doesn't NEED it. It has a rich legacy of its own films and TV shows PLUS a legacy of creativity; THAT'S what Disney should be drawing on for new park attractions. I can't wait for Robert Iger to be shown the door; maybe the new CEO, whoever he or she may be, will "get" people's affection for Disney and sustain and enlarge the parks in a way that honors and enhances Walt's original legacy. I can only hope...
one can only hope