Beca, I just offered this as one possibility, not one we've heard directly from Disney at all. We might look at this from Disney's standpoint. If I were Disney, my first question would be whether offering such a discount would cost me money in ANY way or whether it would make me money. Then I'd beat around the idea of whether it would impact any of the demand for major parks, minor parks, restaurants, shopping, transportation, etc. Then I'd look at resort occupancy.
So if offering a discount that ended up being $100 per person per year and only made me $50 PP/PY at the same time it increased the demand on the systems, wait times, etc; I'd be inclined not to offer that discount. OTOH, if it cost me $100 and made me $150 and did not negatively impact other areas, I'd jump on it. The problem with DVC, as you pointed out, is that essentially those people are going to go and spend money anyway. Maybe some would do more, spend more, go to the parks more (off times), etc; but would the group overall, my guess is no. Still, if it doesn't cost much and gives off a great deal of good will, it might be worthwhile.
Remember that DVC is a significant portion of the on property guests now, maybe 20-25% or so (rough guess). So any risk incurred with offering a benefit is magnified. And even if the numbers work for Disney now, they might not in the future. Hard to take something away that has been there a few years.
So unless it's a CLEAR long term benefit for Disney in general, don't expect much help. And part of the problem with offering a pass that helps some but not others is the complaints for those that can't take advantage. Even though I think they could use it to drive demand if they wanted. To me, the UPH 10% discount is a joke. The discount should be at least 30-40% for members, even with allowing them to drop the first and/or last day.
Having said all that, it's long been my stance that DVC SHOULD offer the same perks to members as they do for FL residents. And since I'm a FL resident and plan to continue to be, it's not for selfish reasons.