I understand the fears of a type of gentrified experience, but to believe there aren't different amenity levels now depending on your credit limit... you are fooling yourself.
I think it's when they start to involve rides that it starts concerning people.
Yes, private tours have been available, but they are very rare and "officially" they make you wait in line, even if in practice they don't.
While many old-timers will point out that WDW used to have a ticket system, it hasn't been that way for thirty years. For thirty years, if you could make your way to Walt Disney World, and pay the admission fee, you could experience the same Magic Kingdom as anyone else.
Now, of course, one family may be out in the parking lot at lunch eating cheese sandwiches out of a cooler, and another may have had lunch in the castle; one family may have a hard time lugging out all the souvenirs they can afford to buy so many, another family may have made two sets of Mickey Ears their big splurge. But the experiences offered in the attractions - shows etc - has always been the same. Mickey Mouse didn't care what hotel you were staying at, or how much your parents were spending. He just wanted to meet
you.
Now, Mickey is going to be happier to meet some guests than other guests. "Why Marissa, you are from Montana, right? I've been waiting for you!" because he read your X-Pass RFID, and the kid standing behind wonders, "Why didn't Mickey know my name?"
There are two ways to look at that. One, "Well, I've got the money to give my kid that experience, tough," and the other is "Well, couldn't Disney do this in a way so they can make their money selling the other luxury things that people will pay for that don't stick out and make others feel left out, and give everyone the same basic park experience?"
Now, in that specific case - maybe there will be separate Mickeys. Who knows. A current example is the Disney Visa character meet. It's right there, but you kinda have to know what you are looking for, and it's rather discrete. Should they roll out X-pass and a lot of people take advantage of it, it likely will not be so discreet.
It goes both ways, too. I'm a single adult with no children, so I can afford a little bit more at WDW should I want. I could probably afford whatever X-pass ends up costing (though if it's tied to hotels, I simply refuse to waste my money staying at Deluxes when I get nothing out of them, and no X-pass would be enough for that price). But I don't like that look on the other family as you whiz past them in line - you see it at Universal when this super happy family is bypassing everyone else because they have unlimited Express. It's not that ubiquitous there, but it creates a definite, visible, class system within the attraction experiences. With Fastpasses now, it's just stupid people who don't know how to use them that get mad (and if they can't follow all the signs, and the maps explaining it in terms a four year old could understand, there are just some people you can't help).
To some this all is inconsequential, but it could have a definite impact on the "magical" feeling we all love so much. It's hard to quantify atmosphere - but in general, the higher tier that exists at WDW is pretty well hidden, or easily overlooked. That would very likely change the "vibe" of how guests feel, about the feelings the whole place gives. Right now, when I sit down at a show next to someone, I have no idea what class they come from or how much they may have spent, and that's great. But if we truly start segregating people even more so than it is now (Dining packages at Fantasmic, etc., which you hear a lot of people moaning about on both sides as it is), the overall feeling in the parks will become even more argumentative and "ME ME ME" than it already has become, because people will be fighting for dibs on whats left over once it's clear the X-pass'ers will take all the "white meat".
It's just not a road I hope we have to travel down.