One thought about why the land may have not been an overwhelming success yet is the premise that we want to visit a world out of the Star Wars universe as ourselves. Didn't Universal try this at first with Harry Potter? To be realistic, the park guests were called muggles -- since obviously they are, in the world of HP. But no one who reads HP wants to be a muggle. My kid immediately wanted to know when his owl might arrive. We want to be wizards and witches, even if it's not realistic. Forget realism!
I don't want to be a plain Jane visitor to a Star Wars planet, I want to fight alongside Leia, or better yet, be Leia. I want Han Solo to secretly have a crush on me (well, maybe that's just me....) I don't want to go on a "realistic" errand to get fuel, I want to have the fate of the galaxy in my hands. So in some ways, immersion is only part of the point. I want to live a fantasy life (to the extent that's possible in a theme park). This is probably not true for everyone (I'm a bit of a nerd), but I think it may account for a little bit of the lackluster opinions.