There is a certain base level of experience that ought to be offerred to every guest, but I don't at all mind offering additional things beyond that to those willing to pay. Backstage tours, character meals, and cabanas at water parks and pools are, IMO, great examples of things Disney can offer and charge extra for that don't bother the guest who chooses not to pay for them.
When they start offering those who pay extra shorter waiting times, exclusive access or reserved seating to shows, and longer hours in the parks, I think they tread on dangerous grounds. Note that the last two already happen, however (EMH and Fantasmic dinner packages) and have not caused much of an uproar amongst guests who don't pay for them. Extra fastpasses for those staying on-site, with even more fastpasses for those staying in Deluxe resorts on-site...we'll see how that goes.